url传值，中文编码问题

var contentData = encodeURIComponent(contents);

task_details?adid="+adid+"&pid="+pid+"&src="+src+"&tid="+tid+"&contents="+contentData;

String.prototype.getQueryString = function(name){
var reg = new RegExp("(^|&|\\?)"+ name +"=([^&]*)(&|$)"), r;
if ( r=this.match(reg) ) return unescape(r[2]);
return null;
}

var str = window.location.href.getQueryString("contents");
var str1 = decodeURIComponent(str);

var $_GET = (function(){
var url = window.document.location.href.toString();
var u = url.split("?");
if(typeof(u[1]) == "string"){
u = u[1].split("&");
var get = {};
for(var i in u){
var j = u[i].split("=");
get[j[0]] = j[1];
}
return get;
} else {
return {};
}
})();

var demo_str = decodeURIComponent($_GET['contents']);
$('.con').html(demo_str);

还是不行，尝试下面写法：

var txt = decodeURIComponent(decodeURI($_GET['contents']));
//    console.log(txt);
string = txt.replace(/\\n/g,'<br />');
$('.con').html(string);