encode url params for unsafe url

gistfile1.txt

function prep(url) {
	var s = url.split('?');
	if (s.length < 1) { // no qs for this url
		return s;
	}
	var qsPart = s[1];
	var params = qsPart.split('&');
	var result = s[0] + '?'; // url part +
	for (var i = 0; i < params.length; i++) {
		var param = params[i];
		var paramSections = param.split('=');
		if (paramSections.length > 1) {
			var paramName = paramSections[0];
			var paramValue = paramSections[1];
			result += paramName + '=' + encodeURIComponent(paramValue) + '&';
		} else {
			continue;
		}
	}
	if (result.lastIndexOf('&') === result.length - 1) {
		result = result.substr(0, result.length - 1);
	}
	return result;
}

console.log(prep('http://vast.bp3863356.btrll.com/vast/3863356?n=1426410433&br_w=300&br_h=250&br_pageurl=http://localhost:9000/app/#/flash&br_conurl=http://sdk.streamrail.com/demos/debugger/nasa_is_with_you_when_you_fly.mp4'));