【转】JS判断URL

function isURL() {
            var strRegex = "^((https|http|ftp|rtsp|mms)://)?[a-z0-9A-Z]{3}\.[a-z0-9A-Z][a-z0-9A-Z]{0,61}?[a-z0-9A-Z]\.com|net|cn|cc (:s[0-9]{1-4})?/$";
            var re = new RegExp(strRegex);
            if (re.test(document.getElementById("<%=txtServerIP.ClientID %>").value)) {
                alert("成功");
                return true;
            } else {
                alert("失败");
                 return false;
            }
        }

这个比较好：

^((https|http)://)?[w|W]{3}\.[a-z0-9A-Z]+\.(com|net|cn|com\.cn){1}(/([a-zA-Z0-9\-\._\?\,\'/\\\+&amp;%\$#\=~])*)?$