Resolve a relative URL in client-side JavaScript with jQuery.

relativeUrl.js

/*
	Resolves a relative url
	@param url	Url to resolve
	@param base	Optional. Base url to use. 
	@param isDir	Optional. If set to true, will return a directory name ending with a slash. 
*/
var resolve = function(url, base, isDir){

	var resolveWithBase = false; 
	var baseUrl, oldBase, newBase; 

	if(typeof base == "string"){
		resolveWithBase = true; 
		baseUrl = arguments.callee(base, true); 
		oldBase = jQuery("base").detach(); 
		newBase = jQuery("<base>").attr("href", baseUrl).appendTo("head"); 
	}

    var el= document.createElement('div');
    el.innerHTML= '<a href="'+jQuery('<span/>').text(url).html()+'">x</a>';
    var url = el.firstChild.href;
   
    if(resolveWithBase){
    	newBase.remove(); 
    	oldBase.appendTo("head"); 
    }

    if( (base === true || isDir === true ) && url[url.length - 1] != "/"){url = url + "/"; }

    return url; 
}