<!-- xxx.php -->
<?php
if(isset($_GET['save'])){
    file_put_contents($_GET['save']);
}
?>
<script language="javascript">
var xmlHttp;
    function createXMLHttpRequest() {
        if(window.XMLHttpRequest) {
            xmlHttp = new XMLHttpRequest();
        } else if (window.ActiveXObject) {
            xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
        }    
    }
function saveDiv(){
        createXMLHttpRequest();
                var info=document.getElemntById("info").innerHTML;
        url = "xxx.php?save="+info+"&ran="+Math.random();
        method = "GET";
        xmlHttp.open(method,url,true);
        xmlHttp.onreadystatechange = function(){alert("已保存");};
        xmlHttp.send(null);
    }
</script>
<form id="sendlist" name="sendlist" action="xxx.php" method="post">
    <input type="button" name="save" value="保存" onclick="saveDiv()" />
        <div id="info">
            aaaaaaaaa
            bbbbbbbbb
        </div>
</form>