javascript jquery点击（记住旧值）
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jquery click (remember OLD VALUE)
提问by Dezigo
While I click on select element, I need to remember old value of the selected element.
This code works in FF,CHROME and OPERA instead of IE.
当我点击选择元素时，我需要记住所选元素的旧值。
此代码适用于 FF、CHROME 和 OPERA 而不是 IE。
- Remember the old value.
- Choose select option and replace old value remembered with a selected option!
- 记住旧值。
- 选择选择选项并用所选选项替换记住的旧值！
Code:
代码：
$(document).ready(function() {
$('#viewTableOrders tr td > select').click(function() {
oldCurrentPath = $(this).val();
oldId = $(this).attr('title');
oldCurrentDate = $('#viewTableOrders tr#vagon' + oldId + '> td >input.input_ver1').val();
dataAjax = {};
});
/* event on change path */
$('#viewTableOrders tr td > select').change(function() {
//do something... + old value
});
});
回答by Dr.Molle
It looks like the problem is that the 2nd click(choosing new option) will fire before the change-event.
看起来问题在于第二次点击（选择新选项）将在更改事件之前触发。
Try using focus instead of click:
尝试使用焦点而不是单击：
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script>
<select>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>Old value is:<span></span>
<script>
$(document).ready(
function()
{
$('select').focus(function()
{
//store old value
$(this).data('oldValue',$(this).val());}
);
$('select').change(function()
{
//do something
$('span').text($(this).data('oldValue'));
//trigger focus to set new oldValue
$(this).trigger('focus');
});
}
);
</script>
(Example also uses data suggested by prodigitalson)
（示例还使用 prodigitalson 建议的数据）
回答by prodigitalson
I would use the datainfrastructure for this:
我会为此使用data基础设施：
$('#viewTableOrders tr td > select').click(function() {
var old = {};
old.currentPath = $(this).val();
old.id = $(this).attr('title');
old.currentDate = $('#viewTableOrders tr#vagon' + old.id + '> td >input.input_ver1').val();
old.ajaxData = {};
$(this).data('oldData', old);
}).change(function() {
var oldData = $(this).data('oldData');
if(typeof old == 'object'){
// do stuff with oldData
}
});
回答by Matt
The question is a little old, but I think we also need to look at the key up/down events, otherwise using the cursor to change the select values doesn't cause the old value to get updated. This worked for me, based on @Dr.Molle's code:
问题有点老了，但我认为我们还需要查看键上/下事件，否则使用光标更改选择值不会导致旧值更新。这对我有用，基于@Dr.Molle 的代码：
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script>
<select>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>Old value is:<span></span>
<script>
$(document).ready(
function()
{
$('select').focus(function()
{
//store old value
$(this).data('oldValue',$(this).val());
});
$('select').change(function()
{
//do something
$('span').text($(this).data('oldValue'));
//trigger focus to set new oldValue
$(this).trigger('focus');
});
$('select').keydown(function()
{
//store old value
$(this).data('oldValue',$(this).val());
});
$('select').keydown(function()
{
//do something
$('span').text($(this).data('oldValue'));
//trigger focus to set new oldValue
$(this).trigger('focus');
});
}
);
</script>
