jQuery Youtube URL Validation with regex

I know there is plenty of question answered over here https://stackoverflow.com/questions/tagged/youtube+regex, but not able find a question similar to me.

Any body has the JavaScript Regular expression for validating the YouTube VIDEO URL’s line below listed. Just want to know where such a URL can be possible

http://www.youtube.com/watch?v=bQVoAWSP7k4

— update 1– — update 2–

This one worked almost fine, but failed for the URL http://youtube.com/watch?v=bQVoAWSP7k4

var matches = $('#videoUrl').val().match(/http://(?:www.)?youtube.*watch?v=([a-zA-Z0-9-_]+)/);
if (matches) {
    alert('valid');
} else {
    alert('Invalid');
}

Answer

^http://(?:www.)?youtube.com/watch?v=w+(&S*)?$

//if v can be anywhere in the query list

^http://(?:www.)?youtube.com/watch?(?=.*v=w+)(?:S+)?$