怎麽用ajax的post向服務器發送請求

function startXMLHttp(){

createXMLHttp();

var send_string="name="+document.getElementById("name").value;

send_string= encodeURI(send_string)

xmlHttp.onreadystatechange =stataHandler;

xmlHttp.open("post","ajax_show.php",true);

// xmlHttp.setRequestHeader("cache-control","no-cache");

// 以下兩句用POST 時不可少，LZ 參考下

xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");

xmlHttp.send(send_string); //發送

}