JS校验URL是否合法

checkURL = function (URL) {
     var str = URL;
     //判断URL地址的正则表达式为:http(s)?://([\w-]+\.)+[\w-]+(/[\w- ./?%&=]*)?
     //下面的代码中应用了转义字符"\"输出一个字符"/"
     var Expression = /http(s)?:\/\/([\w-]+\.)+[\w-]+(\/[\w- .\/?%&=]*)?/;
     var objExp = new RegExp(Expression);
     if (objExp.test(str) == true) {
         return true;
     } else {
         return false;
    }
 }