Prevent the use of symbols - Printable Version

Code:
<!DOCTYPE html>

&lt;html&gt;

&lt;head&gt;

    &lt;title&gt;Character Input Limiter&lt;/title&gt;

    &lt;meta http-equiv="Content-Type" content="text/html; charset=utf-8"&gt;

    [removed][removed]

&lt;/head&gt;

&lt;body&gt;

    <br>

    &lt;form id="myform" action=""&gt;

        <label for="element1">Alpha only</label>

        &lt;input id="element1" name="mytext1" type="text"&gt;

        <br />

        <label for="element2">Alpha numeric + some extras</label>

        &lt;input id="element2" name="mytext2" type="text"&gt;

        <br />

        <label for="element3">Numeric only</label>

        &lt;input id="element3" name="mytext3" type="text"&gt;

        <br />

        <label for="element4">Numeric + some extras</label>

        &lt;input id="element4" name="mytext4" type="text"&gt;

        <br />

        <label for="element5">Direct regular expression</label>

        &lt;input id="element5" name="mytext4" type="text"&gt;

    &lt;/form&gt;

[removed]

    /*

    DISALLOWED INPUT CHARACTERS

    */

    (function($){

        $.fn.disableChars = function(a) {



            /* bring in any modifications to allow */

            a = $.extend({

                allow: '',

                limit_to: '',

                direct_regex: null

            }, a);



            /* create the character base alpha, numeric, or alphanumeric (default) */

            if(a.limit_to == 'alpha'){

                charbase = 'a-z';

            }else if(a.limit_to == 'numeric'){

                charbase = '0-9';

            }else{

                charbase = 'a-z0-9';

            }



            /* convert allow string to regex */

            allowed = a.allow.split('');

            for ( i=0; i<allowed.length; i++){

                allowed[i] = "\\" + allowed[i];

            }

            a.allow = allowed.join('');



            /* combine character base with allowed chars and create regex object */

            if(a.direct_regex == null){

                var regex = new RegExp('[^' + charbase + a.allow + ']', 'ig');

            }else{

                var regex = a.direct_regex;

            }



            /* monitor events on designated elements */

            $(this)

            .bind('keyup blur', function() {

                if (this.value.search(regex) != '-1') {

                    this.value = this.value.replace(regex, '');

                }

            })

            .bind('contextmenu',function () {return false});



        }

    })(jQuery);



    $("#element1").disableChars({limit_to:"alpha"});

    $("#element2").disableChars({allow:".,:-() "});

    $("#element3").disableChars({limit_to:"numeric"});

    $("#element4").disableChars({limit_to:"numeric",allow:"-()."});

    $("#element5").disableChars({direct_regex:/[^-A-Z0-9~!#&*()_+:\'",.?]/ig});

[removed]

&lt;/body&gt;

&lt;/html&gt;