Simple Javascript Regex
some overview about what JS offer in terms of regex http://www.javascriptkit.com/javatutors/redev3.shtml more info about the use of RegExp object \ http://www.w3schools.com/jsref/jsref_obj_regexp.asp and a simple example i found somewhere for PW check: $( function () { $( '#txtNewPW' ).keyup( function () { $( 'div.errorRegexPw' ).hide(); var inputVal = $( this ).val(); var numericReg = /<% = PWRegex %>/; if (!numericReg.test(inputVal)) { $( this ).after( '<div class="errorRegexPw">Not A Valid Password.</div>' ); } }); }); thing is that to init the RegExp obj u just need to do var regex = /pattern/; with the 2 '/'. now all u need to do is regex.test(string_to_test) and get true or false like: var regex = /ariel/; var t = regex.test( "ariel" ); var f = regex.test( "arik" ); here t will be t