javascript 模拟监听功能-优快云博客

本文探讨了在局部刷新页面场景下，如何有效利用监听机制避免服务器资源过度消耗，通过对比setInterval与setTimeout的不同应用，提供了针对特定需求的优化策略。

setInterval(initLogo,6000);
function initLogo(){
//对需要监听的对象监听
setInterval(initLogo,6000);
}
如果是局部刷新页面（监听），则不能使用这种方法，因为页面没有刷新，请求是每隔一段时间就会发送请求，这样请求数量就会以指数增长，这样会导致server崩溃

function listening(){
//对需要监听的对象监听
setTimeout(listening;6000);
}
则不会出现上面描述的问题

function whichElement(e)
{
    var targ;
    var path = "<" + currenPath + ">";
    if (SDCARD_STATU_ENABLED != sdCardStatu)
    {
        alert(dj('sd_label_no_sd_card'));
        return;
    }
    if (!e)
    {
        var e=window.event;
    }

    if (e.target)
    {
        targ=e.target;
    }
    else if (e.srcElement)
    {
        targ=e.srcElement;
    }
    if (targ.nodeType==3) // defeat Safari bug
    {
        targ = targ.parentNode;
    }

    if (window.win && (window.win.closed == false))
    {
        window.win.close();
    }
    path = path.replace(/\%/g, "%25");
    path = path.replace(/\ /g, "%20");
    path = path.replace(/\</g, "%3C");
    path = path.replace(/\>/g, "%3E");
    path = path.replace(/\//g, "%2F");
    path = path.replace(/\&/g, "%26");
    path = path.replace(/\=/g, "%3D");
    path = path.replace(/\#/g, "%23");
    var url = 'sd_upload.htm?path='+path;
    win = window.open(url, 'tree', 'scrollbars=yes,resizable=no,width=720,height=480');
    watchChildWin();
    $("#button_upload").attr("disabled", true);
    $("#button_upload").css("color", "#ACA899");
}

function watchChildWin()
{
    try
    {
        if ( null == win.document || (win.closed == true)) //firefox Google Opera
        {
            setControlDisable("button_upload", false);
            $("#button_upload").attr("style", "color:#000000");
        }
        else
        {
            setTimeout("watchChildWin()", 100);
        }
    }
    catch(e) //ie
    {
        setControlDisable("button_upload", false);
        $("#button_upload").attr("style", "color:#000000");
    }
}