on单击javascript:navigation with changeing css background imag

"Leistungen"具有类lmark，而"Impressum"具有imark。用于lmark类元素的Javascript函数会重置所有其他lmark类的元素的背景，但不会重置imark类的背景。与imark相关的函数也是如此。

如果您需要所有lmark和imark元素只有一个非默认背景，则正确的（可能是正确的，但未测试）代码是：

function li_mark(cell) {
    var elts=document.getElementById("up").getElementsByTagName("li"); //store the elements we need in a local variable so we don't have to rewrite all that line (and the browser won't have to do the fetching job again), we don't care if they're L-type or I-type
    for(var i in elts)
        if(elts[i].className && elts[i].className.length>=8) //check if there is a className and it is at least as long as "uplink-X", otherwise we don't process the element and skip to the next
            elts[i].className="uplink-"+elts[i].className.charAt(7); //we retrieve the letter for the type of class (L or I), and we append it to "upload-" to redefine the class of the current element
    cell.className+="-active"; //after the loop, all elements have their default class, so we just need to append "-active" to the one we want to be active
}

然后，所有对l_mark(this)和i_mark(this)的调用都应该简单地替换为对li_mark(this)的调用。

附言：没有关联，但我目前的浏览器（Firefox）似乎不喜欢window.onload=setActive;，说"没有定义setActive"。。。

根据评论进行编辑，已看到您的JS文件（scripttests.js）：

您仍然需要两个函数，mark()和li_mark()，因为对于mark()，您的活动类的形式是<className>active，而不是<className>-X-active（在命名类时的模式不同，并且不需要检索字符Lor I）。

问题的另一部分是，在一个函数中，在同一个单元格上调用cell.className+="-active"两次。

问题的最后一部分是，您忘记了第二个循环的if中的指令：由于没有块括号，当这个if为true时执行的指令是cell.className+="-active"。。。执行与循环运行一样多的次数并且CCD_ 15为真。

一个（可能）工作版本是：

function li_mark(cell) {
    var elts=document.getElementById("up").getElementsByTagName("li"); //store the elements we need in a local variable so we don't have to rewrite all that line (and the browser won't have to do the fetching job again), we don't care if they're L-type or I-type
    for(var i in elts)
        if(elts[i].className && elts[i].className.length>=8) //check if there is a className and it is at least as long as "uplink-X", otherwise we don't process the element and skip to the next
            elts[i].className="uplink-"+elts[i].className.charAt(7); //we retrieve the letter for the type of class (L or I), and we append it to "upload-" to redefine the class of the current element
    if(cell && cell.className && cell.className.length>=8) { //if we passed an argument, then it must be a cell to activate, with a basic check on its className
        cell.className+="-active"; //after the loop, all elements have their default class, so we just need to append "-active" to the one we want to be active
        mark(); //we call mark() with no argument to reset all the items managed by mark(), we call it in this if-block to avoid infinite recursion
    }
}
function mark(cell) {
    var elts=document.getElementById("nav").getElementsByTagName("li"); //store the elements we need in a local variable so we don't have to rewrite all that line (and the browser won't have to do the fetching job again), we don't care if they're L-type or I-type
    for(var i in elts)
        if(elts[i].className) //check if there is a className, otherwise we don't process the element and skip to the next
            elts[i].className="link"; //we set back to the default class
    if(cell && cell.className) { //if we passed an argument, then it must be a cell to activate
        cell.className+="active"; //after the loop, all elements have their default class, so we just need to append "active" to the one we want to be active
        li_mark(); //we call li_mark() with no argument to reset all the items managed by li_mark(), we call it in this if-block to avoid infinite recursion
    }
}