Validate URL with JavaScript

validateUrl.js

function validateUrl(value)
{
    var expression = /[-a-zA-Z0-9@:%_\+.~#?&//=]{2,256}\.[a-z]{2,4}\b(\/[-a-zA-Z0-9@:%_\+.~#?&//=]*)?/gi
    var regexp = new RegExp(expression);
    return regexp.test(value);
} 

thank you