Javascript validating form input using RE

Usually checking validity of form input involve regular expression.

javascript RE is object it begins with / and ends with /

syntax:

var patt=/pattern/modifiers;

modifiers:

g: global

i: case-insensitive

m: multiple

Check Number:

function checkNumeric(str){var numericExpression = /^[0-9]+$/;return str.match(numericExpression);}

Check Name:

function checkName(str){var exp = /^[ a-zA-Z]+$/;return str.match(exp);}

Check Email:

function checkEmail(str){var emailExp = /^[\w\-\.\+]+\@[a-zA-Z0-9\.\-]+\.[a-zA-z0-9]{2,4}$/;return str.match(emailExp);}

Reference