选择了 jQuery IF 选项
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jQuery IF option selected
提问by iKaspars
I am trying to check with jQuery if the select option with value = 1 is selected then add class to some elements. But something don't work. Can please some one look at the code?
我正在尝试使用 jQuery 检查是否选择了 value = 1 的选择选项，然后将类添加到某些元素。但有些东西不起作用。可以请一些人看一下代码吗？
My code :
我的代码：
Reservation <br/>
<select id="rReservation" name="rReservation" class="">
<option value="0">Maybe</option>
<option value="1">Sure</option>
</select>
<hr/>
Name <br/>
<input type="text" name="rCardUser" class="mRequired" />
<hr/>
Card<br/>
<input type="text" name="rCardNrr" class="mRequired" />
jQuery
jQuery
if ($("#rReservation").val() == "1") {
$('.mRequired').addClass('required');
} else {
$('.mRequired').removeClass('required');
}
LIVE example at fiddle - http://jsfiddle.net/C7Gg3/
小提琴现场示例 - http://jsfiddle.net/C7Gg3/
回答by AlienWebguy
You need it inside an event handler:
您需要在事件处理程序中使用它：
$('#rReservation').change(function(){
$('.mRequired').toggleClass('required', $(this).val() == '1');
});
http://jsfiddle.net/AlienWebguy/C7Gg3/1/
http://jsfiddle.net/AlienWebguy/C7Gg3/1/
If you want it to trigger simply on load, you need to add selected="selected"to one of the options, because until one is "selected", $('#rReservation").val()will be null. Example: http://jsfiddle.net/AlienWebguy/C7Gg3/3/
如果您希望它仅在加载时触发，则需要添加selected="selected"选项之一，因为在“选择”一个选项之前，$('#rReservation").val()将是null. 示例：http: //jsfiddle.net/AlienWebguy/C7Gg3/3/
回答by Joseph Silber
You have to listen to the changeevent:
您必须收听change事件：
$("#rReservation").change(function(){
if ($("#rReservation").val() == "1") {
$('.mRequired').addClass('required');
} else {
$('.mRequired').removeClass('required');
}
});
回答by Matt Ball
Maybe you want to add/remove the class every time the <select>value changes:
也许您想在每次<select>值更改时添加/删除类：
$(function ()
{
$("#rReservation").change()
{
$('.mRequired').toggleClass('required', $(this).val() == "1");
}
});
回答by Jamie Dixon
You have to make sure you've wrapped your code in a change event so that you're listening for the change happening.
您必须确保已将代码包装在更改事件中，以便您可以监听正在发生的更改。
$('#rReservation').change(function(){ /* my code goes here */});
