javascript 获取所选下拉列表项的值
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Get value of selected drop down list item
提问by Java Player
Good Evening, i have these dynamically generated dropdown list in my JSP:`
晚上好，我的 JSP 中有这些动态生成的下拉列表：`
<td><select name="model" id="model" onchange="convertDropDownToTextBox()">
<c:forEach items="${model_list}" var="item">
<option value="${item.modelId}">${item.modelName}</option>
</c:forEach>
<option value="100">Add New Model</option>
</select></td>
and i tried these script to get the selected value from these dropdown :
我尝试了这些脚本以从这些下拉列表中获取选定的值：
function convertDropDownToTextBox(){
var select = document.getElementById("model");
var selectedString = select.options[select.selectedIndex].value;
alert(selectedString);
}
the problem here is that it always gives 1 for every item selected in the dropdown however i f i changed the onChange to be onchange="alert(this.value)"it prints the right values!! how that come? and how to get the actual index of every item selected in the DropDown
这里的问题是它总是为下拉列表中选择的每个项目提供 1 但是如果我将 onChange 更改为onchange="alert(this.value)"它打印正确的值！！怎么来的？以及如何获取在 DropDown 中选择的每个项目的实际索引
回答by louisbros
Not exactly sure what the problem is but this works for me:
不完全确定问题是什么，但这对我有用：
var select = document.getElementById("model");
select.onchange = function(){
var selectedString = select.options[select.selectedIndex].value;
alert(selectedString);
}
回答by Mayer Spitzer
Just pass the eventobject into the Endpoint function:
只需将event对象传递给Endpoint 函数：
<select onchange="convertDropDownToTextBox(event)">
<option value="1">Option 1</option>
</select>
And then you can access the value event.target.valuefrom within the function:
然后您可以event.target.value从函数内部访问该值：
function convertDropDownToTextBox(e) {
console.log(e.target.value);
}
