Deny entering special character in textbox using jquery

How can i deny user fro开发者_开发百科m entering special characters in textbox using jquery?

special characters are like \ / ? * [ or ]

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i think you can achieve this using javascript only

call the below function in KeyPress event of text box

function AlphaNumericOnly(e,isAlphaonly)
{
   // copyright 1999 Idocs, Inc. http://www.idocs.com
   var key = [e.keyCode||e.which];

   var keychar = String.fromCharCode([e.keyCode||e.which]);
   keychar = keychar.toLowerCase();

   if(isAlphaonly=='true')
         checkString="abcdefghijklmnopqrstuvwxyz";
   else 
         checkString="abcdefghijklmnopqrstuvwxyz0123456789";

   if ((key==null) || (key==0) || (key==8) || 
         (key==9) || (key==13) || (key==27) )
        return true;
   else if (((checkString).indexOf(keychar) > -1))
        return true;
   else
        return false;
}

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Using jQuery:

    $(function () {
        //Add handler to input where the id ends with txtName 
        $("input[id$='txtUrl']").keypress(function (event) {
            if (!IsUrlReady(event)) {
                event.preventDefault();
            }
        });
    });

    function IsUrlReady(e) {
        var key = [e.keyCode || e.which];
        var keychar = String.fromCharCode([e.keyCode || e.which]).toLowerCase();

        // 8 = backspace
        // 9 = tab
        //13 = enter key
        //35 = end | #
        //36 = home | $
        //37 - (direction) left | %
        //38 - (direction) up | &
        //39 - (direction) right | '
        //40 - (direction) down | (

        if ((key == null) || (key == 0) || (key == 8) || (key == 9) || (key == 13) || (key == 27) || (key >= 35 && key <= 40)) {
            var pattern = new RegExp("['#$%&\(]");
            return !pattern.test(keychar);
        } else {
            var pattern = new RegExp("[A-Za-z0-9_-]");
            return pattern.test(keychar);
        }
    }

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check the keycodes within a keydown or keyup event handler.

$('input').bind('keydown', function(e){
   if(e.shiftKey){
     switch(e.which){
           case 55:{   // slash
                return(false);
           }
           case 187:{   // *
                return(false);
           }
           // and so forth
     }
   }
});

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Like @Reigel pointed out, listening for keyboard entries can easily be bypassed by simply pasting the content so I think you would be better off with something like the jQuery Validation plugin.

It has tons of features, like custom validation rules so you can have it validate after your own custom rules (obviously). Below is an example of how you can have the validation trigger when the watched field's content changes (rather than waiting until the form is submitted), be it by typing or pasting:

$("#myTextField").change(function() {
    if(!$(this).valid()) {
        /* do something, show an alert, or whatever you need it to do */
    }
});

I won't go into greater detail on how to use this plugin because SO is already full of examples, but I hope it does set you on the right direction.