input type="button" class="body" id="subm" name="subm" value="写好了，发布出去"
onclick="chkfull(this)"/>//注意类型是“按钮”
input type="hidden" id="userchksense" name="userchksense" value="?"/>//嵌入一个隐藏的文本框，给Ajax传值

function chkfull(bt){
var content = document.getElementById("usercontent").value;
if(content=="")
{
    alert("正文为必填。");//判断文章内容是否为空
    return false;

}
else
{
    var xHRObject=false;

    if(window.XMLHttpRequest)//判断浏览器内核
    {
        xHRObject=new XMLHttpRequest();
    }
    else if(window.ActiveXObject)
    {
        xHRObject= new ActiveXObject("Microsoft.XMLHTTP");
    }

    function get2()//定义get2函数，给onreadystatechange做准备。本函数不能放在xHRObject.onreadystatechange=get2;的后面
    {
        if(xHRObject.readyState==4 xHRObject.status==200)
        {
            var serverText=xHRObject.responseText;
            if(serverText=="sense")
            {
                if(confirm("你的文章有敏感词汇，确定要发布吗？\n\r【是，发布】将被审核，请等待。\n\r【否，不发布】将返回界面，请修改字句。"))
                {
                    bt.value="正在提交";
                    bt.disabled=true;//关闭按钮
                    document.getElementById("userchksense").value="sense";//改变userchksense的值为sense，这样，post到add.php就能直接检查是否要锁定本文，而不用再次检查文章
                    document.form1.submit();//提交该表单
                }
                else//好像有点多余，不过这样比较保险
                return false;
            }    
            else
            {
                bt.value="正在提交";
                bt.disabled=true;
                document.getElementById("userchksense").value="nonsense";
                document.form1.submit();
            }

        }
    }

    
    var title=document.getElementById("usertitle").value;
    var tag=document.getElementById("usertag").value;
    var intro=document.getElementById("userintro").value;
    var content=document.getElementById("usercontent").value;

    
    var v = "title="+title+"tag="+tag+"intro="+intro+"content="+content;
    xHRObject.open("POST","../ajax/ajax.php",true);    
    xHRObject.setRequestHeader("Content-Type","application/x-www-form-urlencoded");

    xHRObject.onreadystatechange=get2;//此处的get2不能打括号，否则是将函数的返回值赋值给一个变量，而不是将本函数本身赋值给xHRObject.onreadystatechange（注释1）
    xHRObject.send(v);
}

}