which is the most secure way to check variables type javascript

Posted by mck89 on Stack Overflow See other posts from Stack Overflow or by mck89
Published on 2010-05-12T08:02:08Z Indexed on 2010/05/12 8:04 UTC
Read the original article Hit count: 297

Filed under:

JavaScript

|

variables

|

typechecking

Hi, i need to check the type of a variable in javascript, i know 3 ways to do it:

instanceof operator: if(a instanceof Function)

typeof operator: if(typeof a=="function"

toString method (jQuery uses this): Object.prototype.toString.call(a) == "[object Function]"

Which is the most secure way to do type checking beetween these solutions? and why? Please don't tell me that the last solution is better only because jQuery uses that.

© Stack Overflow or respective owner

Related posts about JavaScript

CHAT ROOMs 7 by 6

as seen on Stack Overflow - Search for 'Stack Overflow'
I am looking for chatroom on one page with 7 loggedin users and 6+rows for say 42 users.these users will keep on adding wthnew users.Need urgent help.A PRETTY UNUSUAL Q FOR MOST OF U.What is MORE REQ new features: Usernames are unique to users currently chatting You can see a "currently chatting"… >>> More
Integrating JavaScript Unit Tests with Visual Studio

as seen on Stephen Walter - Search for 'Stephen Walter'
Modern ASP.NET web applications take full advantage of client-side JavaScript to provide better interactivity and responsiveness. If you are building an ASP.NET application in the right way, you quickly end up with lots and lots of JavaScript code. When writing server code, you should be writing… >>> More
Has Javascript developed beyond what it was originally designed to do?

as seen on Programmers - Search for 'Programmers'
I've been talking with a friend about the purpose of Javascript, when and how it should be used, etc. He quoted that: JavaScript was designed to add interactivity to HTML pages [...] JavaScript gives HTML designers a programming tool HTML authors are normally not programmers… >>> More
PHP, javascript, single quote problems with IE when passing variable from ajax post to javascript fu

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi! I have been trying to get this to work for a while, and I suspect there's an easy solution that I just can't find. My head feels like jelly and I would really appreciate any help. My main page.php makes a .post() to backend.php and fetches a list of cities which it echoes in the form of: <li… >>> More
Javascript in XSL that is loaded by Javascript

as seen on Stack Overflow - Search for 'Stack Overflow'
Is there anyway to have javascript run when a XSL sheet has been applied to an XML file by Javascript? I am using a JQuery plugin to apply the sheet to the xml but the javascript that is located inside of the XSL file will not run. I put the Javascript at the bottom of the file and it still does… >>> More

Related posts about variables

System Expandable-String Environment Variables Can’t Reference User Environment Variables

as seen on Super User - Search for 'Super User'
Hi, I’ve run into a bit of a situation with Windows environment variables. I’ve narrowed it down to what may or may not makes sense and/or possibly be by design. It seems that expandable-string environment variables of the local machine cannot reference environment variables of the current user. For… >>> More
Local variables and instance variables

as seen on Stack Overflow - Search for 'Stack Overflow'
Why is it that instance variables are initialised to default values while local variables aren't? >>> More
Arguments, local variables, and global variables in Python

as seen on Stack Overflow - Search for 'Stack Overflow'
In python, there is no way to differentiate between arguments, local variables, and global variables. The easy way to do so might be have some coding convention such as Global variables start with _ and capital letter arguments end with with _ _Global variable = 10 def hello(x_, y_): z =… >>> More
Arguments, local variables, and global variables coding convention in Python

as seen on Stack Overflow - Search for 'Stack Overflow'
In python, there is no way to differentiate between arguments, local variables, and global variables. The easy way to do so might be have some coding convention such as Global variables start with _ and capital letter arguments end with with _ _Gvariable = 10 def hello(x_, y_): z = x_ + y_ Is… >>> More
Difference between putting variables in header vs putting variables in source

as seen on Stack Overflow - Search for 'Stack Overflow'
Say I declare a header file with a variable: int count; Then in the source file, I want to use count. Do I have to declare it as: extern int count Or can I just use it in my source file? All assuming that I have #include "someheader.h". Or should I just declare it in the source file? What is… >>> More