javascript - 在 dropbox 中更改选项时更改 div 的可见性

Question

我的 php 中有这样的代码:

<section id="placeOrder">
<h2>Place order</h2>
Your details
Customer Type: 
<select name="customerType">
    <option value="">Customer Type?</option>
    <option value="ret">Customer</option>
    <option value="trd">Trade</option>
</select>

这些是必须根据所选选项更改其可见性的 div:

<div id="retCustDetails" class="custDetails">
    Forename <input type="text" name="forename" id="forename" />
    Surname <input type="text" name="surname" id="surname" />
</div>
<div id="tradeCustDetails" class="custDetails" style="visibility:hidden">
    Company Name <input type="text" name="companyName" id="companyName" />
</div>

我试过这个javascript:

<script>
document.getElementsByName("customerType").onchange = function () {
    var val = this.options[this.selectedIndex].value;
    document.getElementById("tradeCustDetails").style.visibility = (val == "trd") ? "visible" : "hidden";
    document.getElementById("retCustDetails").style.visibility = (val == "trd") ? "hidden" : "visible";
};
</script>

但是 div tradecustdetails" 没有出现并且 div retCustDetails 仍然在那里。

有人能帮忙吗？

Answer 1

getElementsByName() 返回文档中具有指定名称的所有元素的集合。因此你必须像这样遍历它们:

var x = document.getElementsByName("customerType");
for (var i = 0; i < x.length; i++) {
    // do something with x[i]
}

如果您只使用一个选择元素，那么最好像这样使用 getElementById():

HTML

<select id="customerType" name="customerType">
    <option value="">Customer Type?</option>
    <option value="ret">Customer</option>
    <option value="trd">Trade</option>
</select>

脚本

document.getElementById("customerType").onchange = function () {
    var val = this.options[this.selectedIndex].value;
    document.getElementById("tradeCustDetails").style.visibility = (val == "trd") ? "visible" : "hidden";
    document.getElementById("retCustDetails").style.visibility = (val == "trd") ? "hidden" : "visible";
};