我有一个有条件的下拉菜单,该菜单可以工作,但取决于我在页面上的放置位置。如果我不将其放置在特定位置,则菜单中的位置根本不会填满。问题还在于我想添加第二个条件下拉列表,并且无论我放在哪里都无法使用。所以我的问题是:是否需要在页面上两次添加脚本以对应于我拥有的两种形式?我实际上希望两个下拉列表都填充完全相同的单词。

document.forms[0]['List'+i].length = 1;
document.forms[0]['List'+i].selectedIndex = 0;


我猜想这和那里的[0]有关。我尝试在表单中添加一个ID,然后编写第二个脚本document.forms('myId')[],但这也不起作用。我应该怎么做呢?

<script type="text/javascript">

var categories = [];
categories["startList"] = ["Programming","Science","History","Business and Economics","Software","Languages","Do it Yourself","Others"];
categories["Programming"] = ["Java","C++","C.","Python","Html","Php","Mysql","ObjectiveC","Android","Others"];
categories["Science"] = ["Mathematics","Physics","Biology","Chemistry","Medicine","Astronomy","Statistics","Others"];
categories["Others"] = ["All"]

var nLists = 2; // number of lists in the set

function fillSelect(currCat,currList){
    var step = Number(currList.name.replace(/\D/g,""));
    for (i=step; i<nLists+1; i++) {
        document.forms[0]['List'+i].length = 1;
        document.forms[0]['List'+i].selectedIndex = 0;
    }
    var nCat = categories[currCat];
    for (each in nCat)  {
        var nOption = document.createElement('option');
        var nData = document.createTextNode(nCat[each]);
        nOption.setAttribute('value',nCat[each]);
        nOption.appendChild(nData);
        currList.appendChild(nOption);
    }
}

function getValue( L2, L1) {
    $.post( "", { List1: L1, List2: L2 } );
}

function init() {
    fillSelect('startList',document.forms[0]['List1'])
}

navigator.appName == "Microsoft Internet Explorer" ? attachEvent('onload', init, false) : addEventListener('load', init, false);

</script>




<form action="" method="post">
<select name='List1' onchange="fillSelect(this.value,this.form['List2'])">
<option selected>Category</option>
</select>

&nbsp;
<select name='List2' onchange="getValue(this.value,this.form['List1'].value)">
<option selected >Subcategory</option>
</select>
<input type="Submit">

最佳答案

固定它。我只需要在其中添加一个选择器或一个选择器即可对应我的第二个表单。

 document.forms[1]['List'+i].length = 1;
            document.forms[1]['List'+i].selectedIndex = 0;
        }
        var nCat = categories[currCat];
        for (each in nCat)  {
            var nOption = document.createElement('option');
            var nData = document.createTextNode(nCat[each]);
            nOption.setAttribute('value',nCat[each]);
            nOption.appendChild(nData);
            currList.appendChild(nOption);
        }
    }

    function getValue( L2, L1) {
        $.post( "", { List1: L1, List2: L2 } );
    }

    function init() {
        fillSelect('startList',document.forms[1]['List1'])

08-25 13:21
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