ajax如何post提交表单？

var param='title='+document.form1.title.value+"&Content="+document.form1.Content.value+"&user="+document.form1.user.value+"&boardid="+document.form1.boardid.value+"&actian="+document.form1.actian.value;
var url="Ajax/topicdata.php";
xmlhttp_request.onreadystatechange=function(){
if (xmlhttp_request.readyState==4 && xmlhttp_request.status==200){
}
}
xmlhttp_request.open('POST',url,true);
xmlhttp_request.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
xmlhttp_request.send(param);
return false;
如果这样做，输入“神秘&s=魔塔&v=在&t=魔塔12吧”就会出错

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url要encode一下 encodeURIComponent

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