Allowing only Alphanumeric values [duplicate]

Question

Possible Duplicate:
How to prevent users from entering invalid characters inside an input field

I have 3 textboxes on a page. One of them should allows numbers, the other alphabets and the 3rd either numbers or alphabets.

Since this is the only requirement, I do not want to use the validation plugin, or any other 3rd party plugin. How can I do this by creating my own plugin using pure jQuery?

This is what I have done but I get a feeling that the code will become too long

 $(this).keydown(function(e)         {             var key = e.charCode || e.keyCode || 0;                         return (                 key == 8 ||                  key == 9 ||                 key == 46 ||                 (key >= 37 && key <= 40) ||                 (key >= 48 && key <= 57) ||                 (key >= 96 && key <= 105));         }); 

http://jsfiddle.net/Cvus8/

Can anyone tell me which si the best way to approach this issue?

Answer 1

The better solution might be to go with regular expression based checks. Example below will limit only alphanumeric characters in the field with id text:

$('#text').keypress(function (e) {     var regex = new RegExp("^[a-zA-Z0-9]+$");     var str = String.fromCharCode(!e.charCode ? e.which : e.charCode);     if (regex.test(str)) {         return true;     }      e.preventDefault();     return false; });