Iframe onload似乎不能及时工作

Question

在动态创建了一些iframe、设置了src和onload之后，我希望可以将内容放入数组并对数组进行排序。下一步是删除iframe(有趣的内容已经放入数组中)，并在我的HTML页面上创建一个表。如果在排序前没有设置警报，则数组为空，因为onload在脚本结束前触发。当在排序之前发出警报时，我发现onload过程被触发，数组被填充，一切正常？！！但我不想发出警告，谁能解释一下我做错了什么？这是我的第一个脚本，所以请帮助我理解。

function LoadFile( ) {
var FName, PName, myID, myFrame;
var myBody  = document.getElementById("StartList");
for ( var i = 0; i < FileList.length; i++ ) {
    // Read input file into frame
    FName   = FileList[i].FName;
    PName   = FName + ".html";
    myID    = "iframe" + i;
    // Create frame.
    myFrame = document.createElement("iframe");
    myFrame.setAttribute("id", myID);
    myFrame.setAttribute("width","0");
    myFrame.setAttribute("height","0");
    myFrame.setAttribute('src', PName);
    //Attach onload-event to frame, triggering ReadTableInfo.
    if (myFrame.attachEvent){
        myFrame.attachEvent("onload", function(){
            ReadTableInfo();
        });
    } else {
        myFrame.onload = function(){
            ReadTableInfo();
        };
    }
    myBody.appendChild(myFrame);
}
}

function ReadTableInfo() {
var a = document.getElementsByTagName("iframe")[idx];
var p = FileList[idx].FName;
var b = (a.contentWindow || a.contentDocument);
var td;
if ( b.document) {
    b = b.document;
    // Get and process table with functions and procedures.
    var myTable = b.getElementsByTagName("Table")[5];
    var myList  = myTable.getElementsByTagName("TR");
    var Name = "";
    var Desc = "";
    for ( var j = 0; j < myList.length; j++) {
        Name = myTable.getElementsByTagName("TR") [j].getElementsByTagName("A")[0].innerHTML;
        if ( myTable.getElementsByTagName("TR")[j].getElementsByTagName("TD")[1] != null) {
            td = myTable.getElementsByTagName("TR")[j].getElementsByTagName("TD")[1];
            Desc = td.textContent || td.innerText || "";
        }
        if ( searchval == "" || ( TestVal.test(Name) && searchkey == 1 ) || ( TestVal.test(Desc) && searchkey == 2 ) ) {
            ProcList[ProcList.length++] = new  AddProcList(Name.toLowerCase(), p.toLowerCase(), Desc);
        }
        Name = "";
        Desc = "";
    }
    idx++;
}
}

function UpdateList( opt ) {
searchval = document.getElementById("edtSearchVal").value;
TestVal = new RegExp(".", "i");
if ( searchval !== "" ) {
    if ( opt == 2 ) {
        TestVal = new RegExp(searchval, "i"); // searchpattern for RegExp descriptions
    } else {
        TestVal = new RegExp(searchval.replace(" ","_"), "i"); // searchpattern for RegExp.
    }
}
switch ( opt ) {
    case 1: searchkey = 1;
            break;
    case 2: searchkey = 2;
            break;
    default: 
            searchkey = 3;
}
Init();
// Get package names from index.
SetFileList();  // Determines which external files to examine.
LoadFile();     // Loads the external files into iframes to be used later.

alert("Start generating list, this may take a while."); // Necessary to read frames! Don't know why???

var sortkeys = {FName:"a",PName:"a"}; // Sorting order of ProcList, which will be the listorder.
ProcList.keySort(sortkeys);           // Sort ProcList.
TableCreate();     // Make new table with all entries in ProcList
}

感谢您的评论，只是在这里向他人学习:))

Answer 1

您的LoadFile();正在将内容加载到iframe，并且alert()恰好为完全加载iframe内容提供了足够的时间，因此其余的代码可以正常工作。如果您删除了alert，则其余代码将在加载iframe内容之前立即执行。我建议甚至在iframe页面中也放入onload。然后将此事件传播到父窗口。要访问父容器窗口，您可以在iframe中执行window.parent。