Convert youtube and vimeo link to embed iframe

convertEmbedMedia.js

/**
 * Convert youtube and vimeo link to embed iframe
 */
function convertEmbedMedia(html)
{
    var origin = html;
    var pattern1 = /(?:http?s?:\/\/)?(?:www\.)?(?:vimeo\.com)\/(?:.*\/)?(.+)/g;
    var pattern2 = /(?:http?s?:\/\/)?(?:www\.)?(?:youtube\.com|youtu\.be)\/(?:watch\?v=)?(.+)/g;
    var pattern3 = /([-a-zA-Z0-9@:%_\+.~#?&//=]{2,256}\.[a-z]{2,4}\b(\/[-a-zA-Z0-9@:%_\+.~#?&//=]*)?(?:jpg|jpeg|gif|png))/gi;
    
    if(pattern1.test(html)){
       var replacement = '<iframe width="490" height="240" src="//player.vimeo.com/video/$1" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>';	           
       var html = html.replace(pattern1, replacement);
    }
    
    if(pattern2.test(html)){
        var replacement = '<iframe width="490" height="240" src="http://www.youtube.com/embed/$1" frameborder="0" allowfullscreen></iframe>';
        var html = html.replace(pattern2, replacement);
    }
    
    if(pattern3.test(html)){
        var replacement = '<a href="$1" target="_blank"><img class="sml" src="$1" /></a><br />';
        var html = html.replace(pattern3, replacement);
    }

    if(html == origin)
    {
    	html = "Cannot parse the embed source!, please check your input.";
    }
    
    return html;
}