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  • What is JavaScript, really?

    - by Lord Loh.
    All this started when I was looking for a way to test my webpage for JavaScript conformance like the W3C HTML Validator. I have not found one yet. So let me know if you know of any... I looked for the official JavaScript page and find ECMA Script. These people have standardized a scripting language (I do not feel like calling it JavaScript anymore!) and called it ECMA-262 (Wikipedia). Their latest work is Edition 5.1 JavaScript was developed my Mozilla Corporation and their last stable version is 1.8.5 (see this) which is based on the ECMA's edition 5.1 The Wikipedia page linked mentions dialects. Mozilla's JavaScript 1.8.5 is listed as a dialect along with JScript 9 (IE) and JavaScript (Chrome's V8[Wiki]) and a lot others. Am I to understand that JavaScript 1.8.5 is a derivative of the ECMA-262 and SpiderMonkey[Wiki] is an engine that runs it? And Chrome has its own dialect and V8 engine is the program that runs it? With all these dialects based off ECMA-262, what I can no longer understand is "What is JavaScript"? Are there any truly cross browser scripting languages? Do the various implementers come together to agree on the dialect cross compatibility? Is this effort ECMA?

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  • arrays format (Javascript)

    - by João Melo
    i have a list of users, with minions, something like this: User52: minion10 minion12 User32: minion13 minion11 i've been keeping in an array where the "location" is the id, like this: Users: [52]User minions: [10]minion [12]minion [32]User minions: [13]minion [11]minion so i can access them easily like this: user[UserID].minions[MinionID] (ex: user[32].minions[11]) but when i print it or send it by json i get something like this: {,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,minion,,,,,,,,,,,,,,minion} but should i keep using like this or should i change to something like this: User = function(){ this.minions = ...; this.getMinion = function(value){ for(var m in this.minions){ if(this.minions[m].id == value){ return this.minions[m]; break; } } } } and get it like this: user.getMinion(MinionID); Question: i get better performance using a "short" array but using loops every time i need a minion, or using "long" arrays, but no need for loop and getting values directly from the id "name"?

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  • Javascript Implementation Patterns for Server-side MVC Websites

    - by tmo256
    I'm looking for information on common patterns for initializing and executing Javascript page by page in a "traditional" server-side MVC website architecture. A few months ago, my development team began, but abandoned, a major re-architecture of our company's primary web app, including a full front-end redesign. In the process, there was some debate about the architecture of the Javascript in the current version of the site, and whether it fit into a clear, modern design pattern. Now I've returned to the process of overhauling the front end of this and several other MVC websites (Ruby on Rails and MVC.net) to implement a responsive framework (Bootstrap), and in the process will again need to review then revamp and update a lot of Javascript. These web applications are NOT single-page Javascript applications (in fact, we are ripping out a lot of Ajax) or designed to require a Javascript MVC pattern; these apps are basically brochure, catalog and administrative sites that follow a server-side MVC pattern. The vast majority of the Javascript required is behavioral, pre-built plugins (JQuery and Bootstrap, et al) that execute on specific DOM nodes. I'm going to give a very brief (as brief as I can be) run-down of the current architecture only in order to illustrate the scope and type of paradigm I'm talking about. Hopefully, it will help you understand the nature of the patterns I'm looking for, but I'm not looking for commentary on the specifics of this code. What I've done in the past is relatively straight-forward and easy to maintain, but, as mentioned above, some of the other developers don't like the current architecture. Currently, on document ready, I execute whatever global Javascript needs to occur on every page, and then call a page-specific init function to initialize node-specific functionality, retrieving the init method from a JS object. On each page load, something like this will happen: $(document).ready(function(){ $('header').menuAction(); App.pages.executePage('home','show'); //dynamic from framework request object }); And the main App javascript is like App = { usefulGlobalVar: 0, pages: { executePage: function(action, controller) { // if exists, App.pages[action][controller].init() }, home: { show: { init: function() { $('#tabs').tabs(); //et. al }, normalizeName: function() { // dom-specific utility function that // doesn't require a full-blown component/class/module } }, edit: ... }, user_profile: ... } } Any common features and functionality requiring modularization or compotentizing is done as needed with prototyping. For common implementation of plugins, I often extend JQuery, so I can easily initialize a plugin with the same options throughout the site. For example, $('[data-tabs]').myTabs() with this code in a utility javascript file: (function($) { $.fn.myTabs = function() { this.tabs( { //...common options }); }; }) Pointers to articles, books or other discussions would be most welcome. Again, I am looking for a site-wide implementation pattern, NOT a JS MVC framework or general how-tos on creating JS classes or components. Thanks for your help!

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  • Populating JavaScript Array from JSP List

    - by tkeE2036
    Ok so perhaps someone can help me with a problem I'm trying to solve. Essentially I have a JSP page which gets a list of Country objects (from the method referenceData() from a Spring Portlet SimpleFormController, not entirely relevant but just mentioning in case it is). Each Country object has a Set of province objects and each province and country have a name field: public class Country { private String name; private Set<Province> provinces; //Getters and setters } public class Province { private String name; //Getters and setters } Now I have two drop down menus in my JSP for countries and provinces and I want to filter the provinces by country. I've been following this tutorial/guide to make a chain select in JavaScript. Now I need a dynamic way to create the JavaScript array from my content. And before anyone mentions AJAX this is out of the question since our project uses portlets and we'd like to stay away from using frameworks like DWR or creating a servlet. Here is the JavaScript/JSP I have so far but it is not populating the Array with anything: var countries = new Array(); <c:forEach items="${countryList}" var="country" varStatus="status"> countries[status.index] = new Array(); countries[status.index]['country'] = ${country.name}; countries[status.index]['provinces'] = [ <c:forEach items="${country.provinces}" var="province" varStatus="provinceStatus"> '${province.name}' <c:if test="${!provinceStatus.last}"> , </c:if> </c:forEach> ]; </c:forEach> Does anyone know how to create an JavaScript array in JSP in the case above or what the 'best-practice' would be considered in this case? Thanks in advance!

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  • Optimizing processing and management of large Java data arrays

    - by mikera
    I'm writing some pretty CPU-intensive, concurrent numerical code that will process large amounts of data stored in Java arrays (e.g. lots of double[100000]s). Some of the algorithms might run millions of times over several days so getting maximum steady-state performance is a high priority. In essence, each algorithm is a Java object that has an method API something like: public double[] runMyAlgorithm(double[] inputData); or alternatively a reference could be passed to the array to store the output data: public runMyAlgorithm(double[] inputData, double[] outputData); Given this requirement, I'm trying to determine the optimal strategy for allocating / managing array space. Frequently the algorithms will need large amounts of temporary storage space. They will also take large arrays as input and create large arrays as output. Among the options I am considering are: Always allocate new arrays as local variables whenever they are needed (e.g. new double[100000]). Probably the simplest approach, but will produce a lot of garbage. Pre-allocate temporary arrays and store them as final fields in the algorithm object - big downside would be that this would mean that only one thread could run the algorithm at any one time. Keep pre-allocated temporary arrays in ThreadLocal storage, so that a thread can use a fixed amount of temporary array space whenever it needs it. ThreadLocal would be required since multiple threads will be running the same algorithm simultaneously. Pass around lots of arrays as parameters (including the temporary arrays for the algorithm to use). Not good since it will make the algorithm API extremely ugly if the caller has to be responsible for providing temporary array space.... Allocate extremely large arrays (e.g. double[10000000]) but also provide the algorithm with offsets into the array so that different threads will use a different area of the array independently. Will obviously require some code to manage the offsets and allocation of the array ranges. Any thoughts on which approach would be best (and why)?

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  • How to access object from array in if condition

    - by Happy
    Accesing array objects in javascript OBJ_ARRAY[j][i] = { "x1": w * i, "y1": h * j, "x2": w * (i + 1), "cell_color": "blue", "y2": h * (j + 1), "name": (i + 1 * (j * 10)) + 1, "z-index": 10, "status":isnotactive } I have this cell array and all its x1,y1 x2,y2 are generated dynamically. for eg. if want to compare OBJ_ARRAY[5][5].x110 then alert if(( OBJ_ARRAY[5][5].x1) > 10)) ; { alert("Done"); } It does not work any idea how it can be fixed?

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  • Advantages of using pure JavaScript over JQuery

    - by Shivan Dragon
    What are the advantages of using Javascript-only versus using JQuery-only? I have limited experience with JavaScript and JQuery coding. I've added bits and snippets of each to HTML pages but I've mostly coded server-side stuff in other languages. I've noticed that while you can theoretically do the same things using either of the two approaches (and of course you can even mix 'em up in the same project) there seems to be a tendency to always start using JQuery from the very beginning no-matter what the project demands are. So I'm simply wondering, are there any punctual benefits to not use JQuery-only but instead to just use plain old JavaScript? I know this looks like a non-question because it can be said about it that "there's no definite answer" or "it can be debated for ever", but I'm actually hoping for punctual answers such as "You can do this in one approach and you cannot do it with the other". ==EDIT== As per scrwtp's comment, I'm not referring just to the DOM Handling part. My question is rather: JQuery is a library. For Javascript. What I find strange about this library as opposed to other libraries for other languages is that in JQyery's case it seems to be designed to be able to use it exclusively and not need to touch Javascript directly. This is as opposed to let's say Hibernate and SQL, where even though the library (or rather framework in this case, but I think the analogy still applies) takes the handle on A LOT of aspects, you still get to use SQL when using it, at least for some fringe cases. However in JQuery & Javascript case, you could do anything you do with Javascript using only JQuery (or at least that's how it seems to me).

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  • Find valid assignments of integers in arrays (permutations with given order)

    - by evident
    Hi everybody! I am having a general problem finding a good algorithm for generating each possible assignment for some integers in different arrays. Lets say I have n arrays and m numbers (I can have more arrays than numbers, more numbers than arrays or as much arrays as numbers). As an example I have the numbers 1,2,3 and three arrays: { }, { }, { } Now I would like to find each of these solutions: {1,2,3}, { }, { } { }, {1,2,3}, { } { }, { }, {1,2,3} {1,2}, {3}, { } {1,2}, { }, {3} { }, {1,2}, {3} {1}, {2,3}, { } {1}, { }, {2,3} { }, {1}, {2,3} {1}, {2}, {3} So basically I would like to find each possible combination to assign the numbers to the different arrays with keeping the order. So as in the example the 1 always needs to come before the others and so on... I want to write an algorithm in C++/Qt to find all these valid combinations. Does anybody have an approach for me on how to handle this problem? How would I generate these permutations?

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  • The importance of Design Patterns with Javascript, NodeJs et al

    - by Lewis
    With Javascript appearing to be the ubiquitous programming language of the web over the next few years, new frameworks popping up every five minutes and event driven programming taking a lead both server and client side: Do you as a Javascript developer consider the traditional Design Patterns as important or less important than they have been with other languages / environments?. Please name the top three design patterns you, as a Javascript developer use regularly and give an example of how they have helped in your Javascript development.

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  • How to use javascript functions, defined in some external *.js file in browser's javascript console?

    - by Dmytro Tsiniavsky
    I would like to know is it possible to save some, for example,simplemath.js file with function ADD(a, b) { return a + b; } simple function, run opera's or some other browser's javascript console, include somehow this (simplemath.js) file, call ADD(2, 5), and get a result in console or execute javascript code on current web page and manipulate with it's content. How can I do that? How can I use javascript functions from external files in web-browser's javascript console?

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  • Javascript click function not working

    - by Nabe
    I need to null the value in text box on click, currently I have written a code as such <div class="keyword_non"> <h1>Keywords : <a class="someClass question_off" title="Keywords "></a></h1> <h2><input type="text" name="kw1" value="one" /></h2> <h2><input type="text" name="kw2" value="two" /></h2> <h2><input type="text" name="kw3" value="three" /></h2> <h2><input type="text" name="kw4" value="four" /></h2> </div> <script type="text/javascript" src="/functions/javascript/custom/non_profit_edit.js"></script> <script type="text/javascript" src="/functions/javascript/jquery-1.7.1.min.js"></script> <script type="text/javascript" src="/functions/javascript/custom/jquery-ui-1.8.7.custom.min.js"></script> Inside non_profit_edit.js i have written as such $(document).ready(function(){ $(".kw1").click(function() { $(".kw1").val(" "); }); $(".kw2").click(function() { $(".kw2").val(" "); }); $(".kw3").click(function() { $(".kw3").val(" "); }); $(".kw4").click(function() { $(".kw4").val(" "); }); }); But write now its not working properly... Is this any browser issues or error in code..

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  • JavaScript parser in JavaScript

    - by emk
    I need to add some lightweight syntactic sugar to JavaScript source code, and process it using a JavaScript-based build system. Are there any open source JavaScript parsers written in JavaScript? And are they reasonably fast when run on top of V8 or a similar high-performance JavaScript implementation? Thank you for any pointers you can provide!

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  • Can google “see” this custom javascript code which displays links from an external site to mine

    - by webmasters
    I have a javascript code on my site who displays links from another site. This is what I have on my source before: <script language="JavaScript" type="text/javascript">showLink(1);</script> This is what I have copied from my source after the page has loaded: <script language="JavaScript" type="text/javascript">showLink(1);</script><a rel="nofollow" target="_blank" class="anc" href="http://x5.external_site.net/sc/out.php?s=5483&amp;o=http%3A%2F%2Fwww.bluetooth.com">Bluetooth Devices</a> Can google see this link?

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  • extjs - 'Store is undefined'

    - by Jamie
    Hi all, I'm pretty sure this a trivial problem and i'm just being a bit stupid. Your help would be hugely appreciated. In controls/dashboard.js I have: Ext.ill.WCSS.controls.dashboard = { xtype:'portal', region:'center', margins:'35 5 5 0', items:[{ columnWidth: 1, style:'padding:10px', items:[{ title: 'My Cluster Jobs', layout:'fit', html: "test" }] },{ columnWidth: 1, style:'padding:10px', items:[{ title: 'All Cluster Jobs', iconCls: 'icon-queue', html: "test", items: new Ext.grid.GridPanel({ title: 'Cluster Job Queue', store: Ext.ill.WCSS.stores.dashboardClusterJobs, width: 791, height: 333, frame: true, loadMask: true, stateful: false, autoHeight: true, stripeRows: true, floating: false, footer: false, collapsible: false, animCollapse: false, titleCollapse: false, columns:[ { xtype: 'gridcolumn', header: 'Job ID', sortable: true, resizable: true, width: 100, dataIndex: 'JB_job_number', fixed: false }, { xtype: 'gridcolumn', header: 'Priority', sortable: true, resizable: true, width: 100, dataIndex: 'JAT_prio', fixed: false }, { xtype: 'gridcolumn', header: 'User', sortable: true, resizable: true, width: 100, dataIndex: 'JB_owner' }, { xtype: 'gridcolumn', header: 'State', sortable: true, resizable: true, width: 100, dataIndex: 'state' }, { xtype: 'gridcolumn', header: 'Date Submitted', sortable: true, resizable: true, width: 100, dataIndex: 'JAT_start_time' }, { xtype: 'gridcolumn', header: 'Queue', sortable: true, resizable: true, width: 100, dataIndex: 'queue_name' }, { xtype: 'gridcolumn', header: 'CPUs', sortable: true, resizable: true, width: 100, dataIndex: 'slots' } ], bbar: { xtype: 'paging', store: 'storeClusterQueue', displayInfo: true, refreshText: 'Retrieving queue status...', emptyMsg: 'No jobs to retrieve', id: 'clusterQueuePaging' } }) }] }] }; Simple enough, note the reference to 'Ext.ill.WCSS.stores.dashboardClusterJobs' So in stores/dashboard.js I just have this: Ext.ill.WCSS.stores.dashboardClusterJobs = new Ext.data.XmlStore({ storeId: 'storeClusterJobs', record: 'job_list', autoLoad: true, url: 'joblist.xml', idPath: 'job_info', remoteSort: false, fields: [ { name: 'JB_job_number' }, { name: 'JAT_prio' }, { name: 'JB_name' }, { name: 'JB_owner' }, { name: 'state' }, { name: 'JAT_start_time' }, { name: 'slots' }, { name: 'queue_name' } ] }); I run the code and I get 'store is undefined' :S It's confusing me a lot. All of the javascripts have been included in the correct order. i.e. <script type="text/javascript" src="/js/portal.js"></script> <script type="text/javascript" src="/js/stores/dashboard.js"></script> <script type="text/javascript" src="/js/controls/dashboard.js"></script> Thanks guys!

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  • Javascript Array Scope - newbie here

    - by Gianluca
    So, I am learning Javascript while playing white Google Calendar APIs and I just can't figure how this piece of code is working this way: var entriesResult = []; var data = new Date(2010,3,22,17,0,0); var callback = function(result) { var entries = result.feed.getEntries(); if (entries.length != 0) { entriesResult = eventsManager(entries, 0, data); window.alert("inner entriesResult " + entriesResult.length); } } this.service.getEventsFeed(this.query, callback, handleGDError); window.alert("outer entriesResult " + entriesResult.length); eventsManager() is a function that returns an array of Objects. getEventsFeed() it's an API function: it queries the service and pass a "feed root" (a feed with selected items) to the callback function. Why the first alert (inner..) outputs a valid entriesResult.length while the second one (outer..) always outputs a 0? I tought javascript arrays are always passed by reference, what's wrong whit my code? Thank you :)

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  • Focus on Javascript or Jquery?

    - by daxflame
    Hello, I am a student in college, and I notice that a lot of companies look for people who have experience with Javascript. Does this include Javascript's libraries, like JQuery? Or, are they looking for Javascript people only? It probably depends on the company, but what is the general advice for a student wanting to do some front end work? Is Javascript more powerful than JQuery? I know Jquery is a library and simplifies many tasks, but is there some reason why you would use Javascript over Jquery?

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  • Remove Duplicates from JavaScript Array

    - by kramden88
    This seems like such a simple need but I've spent an inordinate amount of time trying to do this to no avail. I've looked at other questions on SO and I haven't found what I need. I have a very simple JavaScript array such as peoplenames = new Array("Mike","Matt","Nancy","Adam","Jenny","Nancy","Carl"); that may or may not contain duplicates and I need to simply remove the duplicates and put the unique values in a new array. That's it. I could point to all the codes that I've tried but I think it's useless because they don't work. If anyone has done this and can help me out I'd really appreciate it. JavaScript or jQuery solutions are both acceptable.

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  • How can i put my form value in javascript array

    - by Lucas van den Abbeele
    I want to make a script where i can put my form in the javascript array invoer[] and display the total It constantly stops working and i searched a lot, i really can't find the right way :D This is my javascript code var strijk = ['broek', 'hemd', 'tshirt', 'lakens', 'korte broek', 'babykledij']; var minuten = [5, 10, 5, 6, 3, 3]; function invoerstrijk() { document.write("<form action='' method='get' name='strijkform'>"); for (var a = 0; a < minuten.length; a++) { document.write(strijk[a] + "<input id='" + strijk[a] + "' name ='" + strijk[a] + "' type='text' />" + "<BR>"); } document.write("<button onclick='opgeven()'>opgeven</button>"); document.write("</form>"); } function opgeven() { var invoer = []; for (var a = 0; a < minuten.length; a++) { invoer[a] = document.getElementByI(strijk[a]).value; } var totaal; for (var a = 0; a < minuten.length; a++) { totaal += parseint(invoer[a]) * parseint(minuten[a]); } document.write("<input name=" + strijk[a] + " type='text' value=" + invoer[a] + " readonly />"); if (invoer != []) { document.write("totaal aantal minuten" + totaal); } else { document.write("geen invoer"); } } my html looks likes this <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Untitled Document</title> </head> <body> <script type="text/javascript" > //my javasccript </script> <button id="B1" onclick="invoerstrijk()" >Nieuwe strijk</button> </body> </html>

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  • Populate javascript array with PHP array of Variables

    - by user1704514
    The following code is used to populate a pie chart in javascript: <script type="text/javascript"> var agg = { label: 'Aggressive', pct: [60, 10, 6, 30, 14, 10] }, bal = { label: 'Balanced', pct: [24, 7, 2, 18, 13, 36] }, mod = { label: 'Moderate', pct: [12, 4, 2, 10, 11, 61] }, inc = { label: 'Income', pct: [ 0, 0, 0, 0, 0,100] }, </script> Instead of tm: [40, 60, 67, 30, 74, 50] as seen above, I would like to make each of 6 values a php variable. Like: tm: [$r1, $r2, $r3, $r4, $r5, $r6] . How do I do this? How do I do this with? A php array or json encode?

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  • Why is HTML/Javascript minification beneficial

    - by Channel72
    Why is HTML/Javascript minification beneficial when the HTTP protocol already supports gzip data compression? I realize that Javascript/HTML minification has the potential to significantly reduce the size of Javascript/HTML files by removing unnecessary whitespace, and perhaps renaming variables to a few letters each, but doesn't the LZW algorithm do especially well when there are many repeated characters (e.g. lots of whitespace?) I realize that some Javascript minification tools do more than just reduce size. Google's closure compiler, for example, also tries to improve code performance by inlining functions and doing other analyses. But the primary purpose of Javascript minification is usually to reduce file size. I also realize there are other reasons you might want to minify aside from performace, such as code obfuscation. But again, that reason is not usually emphasized as much as performance gain and file size reduction. For example, Closure Compiler is not advertised as an obfuscation tool, but as a code size reducer and download-speed enhancer. So, how much performance do you really gain from Javascript/HTML minification when you're already significantly reducing file size with gzip compression?

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  • How important is graceful degradation of JavaScript? [closed]

    - by Stephen
    Should web developers continue to spend effort progressively enhancing our web applications with JavaScript, ensuring that features gracefully degrade, thereby ensuring accessibility? Or should we spend that time focused on new features or other areas of development? The subtext of that question would be: How many of our customers/clients/users utilize our websites or applications with JavaScript disabled? Do you have any projects with requirements that specifically demand JavaScript functionality (almost all of mine do), and do those requirements also demand graceful degradation? For the sake of asking this question, I pulled up programmers.stackexchange.com without JavaScript enabled, and I was greeted with this message: "Programmers - Stack Exchange works best with JavaScript enabled". It was difficult to log in, albeit the site seemed to generally work okay. (I wasn't able to vote up any questions.) I think this is a satisfactory approach to development. Imagine the effort involved in making all of the site's features work with plain old HTML and server-side logic. On the other hand, I wonder how many users have been alienated by this approach. We've all been trained (at least the good developers among us) to use progressive enhancement and to ensure our web applications' dynamic features degrade gracefully. Is this progressive enhancement just pissing into the wind, or do some of our customers actually utilize certain web services without JavaScript enabled?

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  • Javascript: Machine Constants Applicable?

    - by DavidB2013
    I write numerical routines for students of science and engineering (although they are freely available for use by anybody else as well) and am wondering how to properly use machine constants in a JavaScript program, or if they are even applicable. For example, say I am writing a program in C++ that numerically computes the roots of the following equation: exp(-0.7x) + sin(3x) - 1.2x + 0.3546 = 0 A root-finding routine should be able to compute roots to within the machine epsilon. In C++, this value is specified by the language: DBL_EPSILON. C++ also specifies the smallest and largest values that can be held by a float or double variable. However, how does this convert to JavaScript? Since a Javascript program runs in a web browser, and I don't know what kind of computer will run the program, and JavaScript does not have corresponding predefined values for these quantities, how can I implement my own version of these constants so that my programs compute results to as much accuracy as allowed on the computer running the web browser? My first draft is to simply copy over the literal constants from C++: FLT_MIN: 1.17549435082229e-038 FLT_MAX: 3.40282346638529e+038 DBL_EPSILON: 2.2204460492503131e-16 I am also willing to write small code blocks that could compute these values for each machine on which the program is run. That way, a supercomputer might compute results to a higher accuracy than an old, low-level, PC. BUT, I don't know if such a routine would actually reach the computer, in which case, I would be wasting my time. Anybody here know how to compute and use (in Javascript) values that correspond to machine constants in a compiled language? Is it worth my time to write small programs in Javascript that compute DBL_EPSILON, FLT_MIN, FLT_MIN, etc. for use in numerical routines? Or am I better off simply assigning literal constants that come straight from C++ on a standard Windows PC?

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  • A few questions about how JavaScript works

    - by KayoticSully
    I originally posted on Stack Overflow and was told I might get some better answers here. I have been looking deeply into JavaScript lately to fully understand the language and have a few nagging questions that I can not seem to find answers to (Specifically dealing with Object Oriented programming. I know JavaScript is meant to be used in an OOP manner I just want to understand it for the sake of completeness). Assuming the following code: function TestObject() { this.fA = function() { // do stuff } this.fB = testB; function testB() { // do stuff } } TestObject.prototype = { fC : function { // do stuff } } What is the difference between functions fA and fB? Do they behave exactly the same in scope and potential ability? Is it just convention or is one way technically better or proper? If there is only ever going to be one instance of an object at any given time, would adding a function to the prototype such as fC even be worthwhile? Is there any benefit to doing so? Is the prototype only really useful when dealing with many instances of an object or inheritance? And what is technically the "proper" way to add methods to the prototype the way I have above or calling TestObject.prototype.functionName = function(){} every time? I am looking to keep my JavaScript code as clean and readable as possible but am also very interested in what the proper conventions for Objects are in the language. I come from a Java and PHP background and am trying to not make any assumptions about how JavaScript works since I know it is very different being prototype based. Also are there any definitive JavaScript style guides or documentation about how JavaScript operates at a low level? Thanks!

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  • Listening and firing events with Javascript and maybe jQuery

    - by at
    In my Javascript and Flex applications, users often perform actions that I want other Javascript code on the page to listen for. For example, if someone adds a friend. I want my Javascript app to then call something like triggerEvent("addedFriend", name);. Then any other code that was listening for the "addedFriend" event will get called along with the name. Is there a built-in Javascript mechanism for handling events? I'm ok with using jQuery for this too and I know jQuery makes extensive use of events. But with jQuery, it seems that its event mechanism is all based around elements. As I understand, you have to tie a custom event to an element. I guess I can do that to a dummy element, but my need has nothing to do with DOM elements on a webpage. Should I just implement this event mechanism myself?

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