hi i have web page which uses ajax to retrieving data from another pages and while doing that i want to show a loading gif in the page so i ve create a div with my gif on it.

 <div id="loading"><img src="images/loadinfo.net.gif" width="48" height="48" /></div>

这是我的css代码：

#content #loading {
    visibility:hidden;
    position: fixed;
    width: 48px;
    top: 0px;
}

now i figured all i need to do is to set the visibility of loading div to visible at the beginning of my loading content ajax function and then at the end make it hidden again but its not working weird thing is if i create loading div visible and then turn it hidden at the beginning of ajax function it works fine !!!

这是我的功能：

function ajaxpage(url, containerid) {
    document.getElementById( loading ).style.visibility =  visible ;

    var bustcachevar = 1 //bust potential caching of external pages after initial request? (1=yes, 0=no)
    var loadedobjects = ""
    var rootdomain = "http://" + window.location.hostname
    var bustcacheparameter = ""

    var page_request = false
    if (window.XMLHttpRequest) // if Mozilla, Safari etc
    page_request = new XMLHttpRequest()
    else if (window.ActiveXObject) { // if IE
        try {
            page_request = new ActiveXObject("Msxml2.XMLHTTP")
        } catch (e) {
            try {
                page_request = new ActiveXObject("Microsoft.XMLHTTP")
            } catch (e) {}
        }
    } else
    return false
    page_request.onreadystatechange = function () {
        loadpage(page_request, containerid)
    }
    if (bustcachevar) //if bust caching of external page
    bustcacheparameter = (url.indexOf("?") != -1) ? "&" + new Date().getTime() : "?" + new Date().getTime()
    page_request.open( GET , url + bustcacheparameter, true)
    page_request.send(null)
}

function loadpage(page_request, containerid) {
    if (page_request.readyState == 4 && (page_request.status == 200 || window.location.href.indexOf("http") == -1)) document.getElementById(containerid).innerHTML = page_request.responseText

}

function loadobjs() {
    if (!document.getElementById) return
    for (i = 0; i < arguments.length; i++) {
        var file = arguments[i]
        var fileref = ""
        if (loadedobjects.indexOf(file) == -1) { //Check to see if this object has not already been added to page before proceeding
            if (file.indexOf(".js") != -1) { //If object is a js file
                fileref = document.createElement( script )
                fileref.setAttribute("type", "text/javascript");
                fileref.setAttribute("src", file);
            } else if (file.indexOf(".css") != -1) { //If object is a css file
                fileref = document.createElement("link")
                fileref.setAttribute("rel", "stylesheet");
                fileref.setAttribute("type", "text/css");
                fileref.setAttribute("href", file);
            }
        }
        if (fileref != "") {
            document.getElementsByTagName("head").item(0).appendChild(fileref)
            loadedobjects += file + " " //Remember this object as being already added to page
        }
    }
    document.getElementById( loading ).style.visibility =  hidden ;
}