jQuery 如何使用jquery检查下拉列表的选定索引不是0或-1
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How to check if selected index of dropdownlist is not 0 or -1 using jquery
提问by Eyla
How to check if selected index of dropdownlist is not 0 or -1 using jquery?
如何使用jquery检查下拉列表的选定索引不是0或-1？
回答by BalusC
Unless you've the actual optionelement to your hands, jQuery doesn't have special facilities for this. Just access the element's standard selectedIndexattribute:
除非您拥有实际的option元素，否则jQuery 没有特殊功能。只需访问元素的标准selectedIndex属性：
var selectedIndex = $('#dropdownId').attr('selectedIndex');
if (selectedIndex > 0) {
// ...
}
回答by Glennular
$("select#elem").get(0).selectedIndex > 0
回答by James Drinkard
I had to check to see if selected index was greater than 0, so I used:
我必须检查所选索引是否大于 0，所以我使用了：
if($("select option:selected").index() > 0) {
alert($("select option:selected").index());
}
回答by S Pangborn
Taking a different approach from the others, jQuery can check the "value" of the option, as well.
采用与其他方法不同的方法，jQuery 也可以检查选项的“值”。
<select id="checkme">
<option value="0">0</option>
<option value="-1">-1</option>
</select>
And the jQuery:
和 jQuery：
$(document).ready( function () {
var theValue = $("#checkme").val();
alert("The value of the select is: " + theValue);
});
This way you don't have to know what index maps to what value, you just check the value of the select, and it will tell you what optionis selected.
这样您就不必知道什么索引映射到什么值，您只需检查 的值select，它就会告诉您option选择了什么。
