Javascript 函数 - 适用于 IE，不适用于 chrome

Question

首先，我们是一个小组织，这个系统是很久以前有人建立的。我是 javascript 的新手，所以我在做复杂的事情时遇到了麻烦，但我会尽力理解你的答案。但不幸的是，目前从头开始重做并不是真正的选择。

我们有一个收集数据的系统，客户使用登录名来验证成员(member) ID，然后系统使用该系统将记录从 MS Access 数据库提取到 .ASP/html 表单，以便客户可以更新他们的数据。其中一个页面具有以下功能，该功能在表单提交上运行，以检查字段 a/b/c 中的数据总和是否与 d/e/f/g/h/i 中的总和相同。它对显示的每一列分别执行此操作(每一列是数据库中的一条记录，每个 a/b/c/d/e/f 是记录中的一个字段。)

问题出在函数的这一部分:

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for (var j=0; j<recCnt; j++) {
   sumByType = milesSurf[j] + milesElev[j] + milesUnder[j];
   sumByTrack = milesSingle[j] + milesDouble[j] + milesTriple[j] + milesQuad[j] + milesPent[j] + milesSex[j];

等等

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它应该使用 javascript FOR 循环遍历每条记录并测试它们是否相加。

在 Firefox 和 IE 中这是正常工作的；这些字段正确地汇总为“sumByType”和“sumByTrack”。你可以在下面看到我添加了一个小警报来找出问题所在:

alert(sumByType + ""+ j + ""+ recCnt + ""+ milesSurf[j] + ""+ milesElev[j] + ""+ milesUnder[j]);

在 Chrome 中，该警报告诉我“sumByType”和“sumByTrack”(各种“milesXXXXX”变量)的组件未定义。

我的问题是:为什么这在 Chrome 中不能正常工作，而在 IE 和 FFox 中却能正常工作？有什么想法吗？

完整功能代码如下:

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function submitCheck(formy, recCnt) {
//2/10/03: added milesQuad
//---------------checks Q#4 that Line Mileage by type is the same as by track     
var milesElev = new Array(); 
var milesSurf = new Array();
var milesUnder = new Array(); 
var milesSingle = new Array();
var milesDouble = new Array(); 
var milesTriple = new Array();
var milesQuad = new Array();
var milesPent = new Array();
var milesSex = new Array();
var sumByType = 0;
var milesLineTrack = new Array();   //this is for Q5 to compare it to mileage by trackage
var j = 0; var sumByTrack = 0; var liney; var yrOp;
//var str = "document.frm.milesElev" + j;
//alert(str.value);
for (var i in document.frm) {
    if (i.substring(0, i.length - 1) == "milesElev") {
        milesElev[parseInt(i.substring(i.length-1, i.length))] = parseFloat(document.frm[i].value); }   
    if (i.substring(0, i.length - 1) == "milesSurf") {
        milesSurf[parseInt(i.substring(i.length-1, i.length))] = parseFloat(document.frm[i].value); }
    if (i.substring(0, i.length - 1) == "milesUnder") {
        milesUnder[parseInt(i.substring(i.length-1, i.length))] = parseFloat(document.frm[i].value); }
    if (i.substring(0, i.length - 1) == "milesSingle") {
        milesSingle[parseInt(i.substring(i.length-1, i.length))] = parseFloat(document.frm[i].value); }
    if (i.substring(0, i.length - 1) == "milesDouble") {
        milesDouble[parseInt(i.substring(i.length-1, i.length))] = parseFloat(document.frm[i].value); }
    if (i.substring(0, i.length - 1) == "milesTriple") {
        milesTriple[parseInt(i.substring(i.length-1, i.length))] = parseFloat(document.frm[i].value); }
    if (i.substring(0, i.length - 1) == "milesQuad") {
        milesQuad[parseInt(i.substring(i.length-1, i.length))] = parseFloat(document.frm[i].value); }
    if (i.substring(0, i.length - 1) == "milesPent") {
        milesPent[parseInt(i.substring(i.length-1, i.length))] = parseFloat(document.frm[i].value); }
    if (i.substring(0, i.length - 1) == "milesSex") {
        milesSex[parseInt(i.substring(i.length-1, i.length))] = parseFloat(document.frm[i].value); }
    if (i.substring(0, i.length -1) == "milesLineTrack") {
        milesLineTrack[parseInt(i.substring(i.length-1, i.length))] = document.frm[i].value; }  //12/13/02 used to be parseFloat(document.frm[i].value)
    if (i.substring(0,5)=="Lines") {
        liney = document.frm[i].value;
    if (parseInt(liney)<1 || isNaN(liney)) {
        alert("Each mode must have at least 1 line.  Please correct the value in question #2."); 
        document.frm[i].select(); return false; }}
    if (i.substring(0,8)=="yearOpen") { 
        yrOp = document.frm[i].value;
        if (parseInt(yrOp)<1825 || isNaN(yrOp)) {
            alert("Please enter a year after 1825 for question #3"); 
            document.frm[i].select(); return false; }
    }
}
for (var j=0; j<recCnt; j++) {
    sumByType = milesSurf[j] + milesElev[j] + milesUnder[j];
    sumByTrack = milesSingle[j] + milesDouble[j] + milesTriple[j] + milesQuad[j] + milesPent[j] + milesSex[j];

    //---------------to round sumByTrack and sumByType from a long decimal to a single decimal place, like frm 7.89999998 to 7.9.
    sumByTrack = sumByTrack * 10;
    if (sumByTrack != parseInt(sumByTrack)) {
        if (sumByTrack - parseInt(sumByTrack) >= .5) {
        //round up
            sumByTrack = parseInt(sumByTrack) + 1; }
        else {  //truncate
            sumByTrack = parseInt(sumByTrack); }}
    sumByTrack = sumByTrack / 10;
    sumByType = sumByType * 10;
    if (sumByType != parseInt(sumByType)) { 
        if (sumByType - parseInt(sumByType) >= .5) {
        //round up
            sumByType = parseInt(sumByType) + 1; }
        else {  //truncate
            sumByType = parseInt(sumByType); }}
    sumByType = sumByType / 10;
    //-------------end of rounding ---------------------------

    if (sumByType != sumByTrack) {
        if (isNaN(sumByType)) { 
            sumByType = "(sum of 4.a., b., and c.) "; }
        else {
            sumByType = "of " + sumByType; }
        if (isNaN(sumByTrack)) { 
            sumByTrack = "(sum of 4.d., e., f., g., h., and i.) "; }
        else {
            sumByTrack = "of " + sumByTrack; }
        alert("For #4, the 'End-to-End Mileage By Type' " + sumByType + " must equal the 'End-to-end Mileage By Trackage' " + sumByTrack + ".");
        alert(sumByType + " " + j + " " + recCnt + " " + milesSurf[j] + " " + milesElev[j] + " " + milesUnder[j]);
        return false;
    }
    //alert (milesLineTrack[j] + "  " + milesSingle[j] + "  " + 2*milesDouble[j] + "  " + 3*milesTriple[j] + "  " + 4*milesQuad[j] + "  " + 5*milesPent[j] + "  " + 6*milesSex[j]);
    var singDoubTrip = (milesSingle[j] + 2*milesDouble[j] + 3*milesTriple[j] + 4*milesQuad[j] + 5*milesPent[j] + 6*milesSex[j])
    //----------round singDoubTrip to one digit after the decimal point (like from 6.000000001 to 6.0)
    singDoubTrip = singDoubTrip * 10;
    if (singDoubTrip != parseInt(singDoubTrip)) { 
        if (singDoubTrip - parseInt(singDoubTrip) >= .5) {
        //round up
            singDoubTrip = parseInt(singDoubTrip) + 1; }
        else {  //truncate
            singDoubTrip = parseInt(singDoubTrip); }}
    singDoubTrip = singDoubTrip / 10;
    //----------end round singDoubTrip-----------------------------------------
    if (parseFloat(milesLineTrack[j]) != singDoubTrip) {
        //var mlt = milesLineTrack[j];
        //if isNaN(milesLineTrack[j]) { mlt = 
        alert("For column #" + (j+1) + ", the mainline passenger track mileage of " + milesLineTrack[j] + " must equal the single track plus 2 times the double track plus 3 times the triple track plus 4 times the quadruple track plus 5 times the quintuple track plus 6 times the sextuple track, which is " + singDoubTrip + ".");
        return false; 
    }
}
//---------------------end of checking Q#4----------------

//return false;

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Answer 1

我认为 for (var i in document.frm) 是问题所在。你不应该枚举一个 form 元素，会有很多意想不到的属性 - 参见 Why is using "for...in" with array iteration a bad idea? ，对于类似数组的对象尤其如此。我不敢相信这在 FF 中可以正常工作 :-)

使用这个:

var ele = document.frm.elements; // or even better document.getElementById("frm")
for (var i=0; i<ele.length; i++) {
    // use ele[i] to access the element,
    // and ele[i].name instead of i where you need the name
}

此外，您应该支持在那些大量的 if 语句上使用循环。