急js5秒调用一次test.php js如何写 没分了哪位帮帮忙

急急急，js5秒调用一次test.php js怎么写 没分了哪位帮帮忙
<input name="send" type="button" id="send" onclick="SendMail();" value=" 调用 " />
js页面
function SendMail()
{
}
js5秒调用一次test.php

[解决办法]
仅供参考：

JScript code

var xmlHttp;var timer = null;var timerRunning = false;var url;    function createXMLHttpRequest() {        if(window.XMLHttpRequest) {            xmlHttp = new XMLHttpRequest();        } else if (window.ActiveXObject) {            xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");        }    }    function statusStop (){        if(timerRunning){              clearTimeout(timer);        }        timerRunning = true;    }    /* ------------------- 间隔查询 ------------------- */    function autoDeep(){        createXMLHttpRequest();        url = "map.php?refresh="+Math.random();        method = "GET";        xmlHttp.open(method,url,true);        xmlHttp.onreadystatechange = null;        xmlHttp.send(null);        timerRunning = false;        timer = setTimeout('autoDeep()',5000);  //5秒执行一次    }    function statusBegin(){        statusStop();        autoDeep();    }    statusBegin();