以下是根据正则判断，url是否是正常的url

 function IsURL(str_url){
   var strRegex = "^((https|http|ftp|rtsp|mms)?://)"
   + "?(([0-9a-z_!~*'().&=+$%-]+: )?[0-9a-z_!~*'().&=+$%-]+@)?" //ftp的user@
         + "(([0-9]{1,3}\.){3}[0-9]{1,3}" // IP形式的URL- 199.194.52.184
         + "|" // 允许IP和DOMAIN（域名）
         + "([0-9a-z_!~*'()-]+\.)*" // 域名- www.
         + "([0-9a-z][0-9a-z-]{0,61})?[0-9a-z]\." // 二级域名
         + "[a-z]{2,6})" // first level domain- .com or .museum
         + "(:[0-9]{1,4})?" // 端口- :80
         + "((/?)|" // a slash isn't required if there is no file name
         + "(/[0-9a-z_!~*'().;?:@&=+$,%#-]+)+/?)$";
         var re=new RegExp(strRegex);
   //re.test()
         if (re.test(str_url)){
             return (true);
         }else{
             return (false);
         }
}