Capture *all* display-characters in JavaScript?
- by Jean-Charles
I was given an unusual request recently that I'm having the most difficult time addressing that involves capturing all display-characters when typed into a text box. The set up is as follows:
I have a text box that has a maxlength of 10 characters. When the user attempts to type more than 10 characters, I need to notify the user that they're typing beyond the character count limit.
The simplest solution would be to specify a maxlength of 11, test the length on every keyup, and truncate back down to 10 characters but this solution seems a bit kludgy. What I'd prefer to do is capture the character before keyup and, depending on whether or not it is a display-character, present the notification to the user and prevent the default action.
A white-list would be challenging since we handle a lot of international data.
I've played around with every combination of keydown, keypress, and keyup, reading event.keyCode, event.charCode, and event.which, but I can't find a single combination that works across all browsers. The best I could manage is the following that works properly in =IE6, Chrome5, FF3.6, but fails in Opera:
NOTE: The following code utilizes jQuery.
$(function(){
$('#textbox').keypress(function(e){
var $this = $(this);
var key = ('undefined'==typeof e.which?e.keyCode:e.which);
if ($this.val().length==($this.attr('maxlength')||10)) {
switch(key){
case 13: //return
case 9: //tab
case 27: //escape
case 8: //backspace
case 0: //other non-alphanumeric
break;
default:
alert('no - '+e.charCode+' - '+e.which+' - '+e.keyCode);
return false;
};
}
});
});
I'll grant that what I'm doing is likely over-engineering the solution but now that I'm invested in it, I'd like to know of a solution. Thanks for your help!
