帮看看这段代码的问题？运行结束时找不到对象

解决方案 »

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window.setInterval("dec()", 1000);
我试过了，放在最后还是同样的错误
function dec() { alert(111)
    time--;
    document.getElementById("time_pad").innerHTML = time;
    if (time == 0) document.getElementById("do_OK").fireEvent("onclick");
}
你会发现这个函数执行了6次
楼上的提醒了我，改了一下，var time = 5;
function dec() {
    if (time == 0) {
        document.getElementById("do_OK").fireEvent("onclick");
    }
    else if (time >= 0) {
        document.getElementById("time_pad").innerHTML = time;
    }
    else {
        return false;
    }
    time--;
}但好像执行第二次时间在跳跃，根本没有到5秒
楼上的提醒了我，改了一下，var time = 5;
function dec() {
    if (time == 0) {
        document.getElementById("do_OK").fireEvent("onclick");
    }
    else if (time >= 0) {
        document.getElementById("time_pad").innerHTML = time;
    }
    else {
        return false;
    }
    time--;
}但好像执行第二次时间在跳跃，根本没有到5秒
好像还有问题，自动关闭不会出错误，但如果是单击确定后就又出现了问题window.setInterval("dec()", 1000);
估计还是在这句上，它不能停止执行
setInterval(表达式,交互时间)
它从载入后,每隔指定的时间就执行一次表达式
要清除计时器<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<script language="javascript" type="text/javascript" >    function aaa() {
        sAlert("asdfasdfa");
        return false;
    }

    var time = 5,timer=null;
function dec() {
    time--;
    document.getElementById("time_pad").innerHTML = time;
    if (time == 0){
      document.getElementById("do_OK").fireEvent("onclick");
      clearInterval(timer);//================清除计时器，因为你删除
      timer=null;
    }
}
function sAlert(txt) {
    time = 5;
    var shield = document.createElement("DIV");
    shield.id = "shield";
    shield.style.position = "absolute";
    shield.style.left = "0px";
    shield.style.top = "0px";
    shield.style.width = "100%";
    shield.style.height = document.body.scrollHeight + "px";
    shield.style.background = "#333";
    shield.style.textAlign = "center";
    shield.style.zIndex = "10000";
    shield.style.filter = "alpha(opacity=0)";
    shield.style.opacity = 0;
    var alertFram = document.createElement("DIV");
    alertFram.id = "alertFram";
    alertFram.style.position = "absolute";
    alertFram.style.left = "50%";
    alertFram.style.top = "50%";
    alertFram.style.marginLeft = "-225px";
    alertFram.style.marginTop = -75 + document.documentElement.scrollTop + "px";
    alertFram.style.width = "450px";
    alertFram.style.height = "150px";
    alertFram.style.background = "#ccc";
    alertFram.style.textAlign = "center";
    alertFram.style.lineHeight = "150px";
    alertFram.style.zIndex = "10001";
    strHtml = " <ul style=\"list-style:none;margin:0px;padding:0px;width:100%\"> \n";
    strHtml += "  <li style=\"background:#DD828D;text-align:left;padding-left:20px;font-size:18px;font-weight:bold;height:25px;line-height:25px;border:1px solid #F9CADE;\">[提示]:     <span id='time_pad' style=\"color:red;font-family:Verdana;font-weight:bold;\">" + time + "</span>秒钟后关闭" + " </li>  \n";
    strHtml += "  <li style=\"background:#fff;text-align:center;font-size:14px;height:120px;line-height:120px;border-left:1px solid #F9CADE;border-right:1px solid #F9CADE;\"> " + txt + " </li> \n";
    strHtml += "  <li style=\"background:#FDEEF4;text-align:center;font-weight:bold;height:25px;line-height:25px; border:1px solid #F9CADE;\"> <input type=\"button\" value=\" 确定 \" id=\"do_OK\" onclick=\"doOk()\" style=\"width:60px\" /> </li> \n";
    strHtml += " </ul> \n";
    alertFram.innerHTML = strHtml;
    document.body.appendChild(alertFram);
    document.body.appendChild(shield);
    this.setOpacity = function(obj, opacity) {
        if (opacity >= 1) opacity = opacity / 100;
        try { obj.style.opacity = opacity; } catch (e) { }
        try {
            if (obj.filters.length > 0 && obj.filters("alpha")) {
                obj.filters("alpha").opacity = opacity * 150;
            } else {
                obj.style.filter = "alpha(opacity=\"" + (opacity * 150) + "\")";
            }
        } catch (e) { }
    }
    var c = 0;
    this.doAlpha = function() {
        if (++c > 20) { clearInterval(ad); return 0; }
        setOpacity(shield, c);
    }
    var ad = setInterval("doAlpha()", 1);
    this.doOk = function() {
        document.body.removeChild(alertFram);
        document.body.removeChild(shield);
        document.body.onselectstart = function() { return true; }
        document.body.oncontextmenu = function() { return true; }
    }
    document.getElementById("do_OK").focus();
    document.body.onselectstart = function() { return false; }
    document.body.oncontextmenu = function() { return false; }

    timer=window.setInterval("dec()", 1000);//=================放最后，防止未生成控件
}</script>
    <title></title>
</head>
<body>
    <form id="form1" >
    <div>
           <input type="submit" ID="Button2" valule="Button"  OnClick=" return aaa()"/>
        <input id="Button1" type="button" value="button" onclick="aaa()" />
    </div>
    </form>
</body>
</html>
谢谢楼上的兄台，可问题依然存在，如果是5秒时间自然过去，不去点确定的话，没有问题发生，但是如果5秒内去点确定，依然提示document.getElementById("time_pad").innerHTML = time;document.getElementById()为空或不是对象
另外有一点我有点怀疑，是不是浏览器的问题，我用的是win server 2003 + IE 8  beta2IE8脚本调式功能貌似很强不知道兄弟们用的是什么 IE测试的
谢谢楼上的兄台，可问题依然存在，如果是5秒时间自然过去，不去点确定的话，没有问题发生，但是如果5秒内去点确定，依然提示document.getElementById("time_pad").innerHTML = time;document.getElementById()为空或不是对象
另外有一点我有点怀疑，是不是浏览器的问题，我用的是win server 2003 + IE 8  beta2IE8脚本调式功能貌似很强不知道兄弟们用的是什么 IE测试的
忘记了，这里也要清楚计时器this.doOk = function() {
      if(timer){clearInterval(timer);timer=null;}//================清除计时器
        document.body.removeChild(alertFram);
        document.body.removeChild(shield);
        document.body.onselectstart = function() { return true; }
        document.body.oncontextmenu = function() { return true; }
    }
谢谢showbo 兄！问题解决，结贴!3Q