jQuery。 脚本更改输入字段中的值。 比基于输入字段中的值需要执行if语句

Question

Here is example jsFiddle

If enter something in First input, then value in the Second and Third input becomes 1 (one).

Then if value in Third input is > 0 then do something, for example alert("Test");

But this if statement does not work. For my eyes value in Third input is 1 (one), but for script seems the value in Third input is empty

How to get execute if statement based on value in Third input?

First input
<br>
<td class='exchange_rate1'>
<input type="text" name="exchange_rate1" id='exchange_rate1' class='exchange_rate_changed1' value="">
</td>
<br>Second input
<br>
<td>
<input type="text" name="is_exchange_rate_changed1" id="is_exchange_rate_changed1" class='exchange_rate_changed_test1'>
</td>
<br>Third input
<br>
<td>
<input type="text" name="is_exchange_rate_changed_test1" id="is_exchange_rate_changed_test1">
</td>


$(".exchange_rate_changed1").on("change", function () {
$('#is_exchange_rate_changed1').val(1).change()
});


$(".exchange_rate_changed_test1").on("change", function () {
$('#is_exchange_rate_changed_test1').val(1).change()
});

if ($("#is_exchange_rate_changed_test1").val() > 0) {
alert("Test");    
}

If question why this is necessary. Then, for example:

1) in first input field user enters currency name (USD)

2) with ajax, based on currency name get currency value in the Second input

3) if currency value in the Second input changes, then changes Third input

4) and latter if user enters amount in currency in Fourth field and Third input value is > 0 , then do calculations

Possible solution Here http://jsfiddle.net/eDCqN/11/ placed possible solution. As I need if to exist / work independently, then created additional function that is executed on $("input").change . So as understand each time when input changes if is executed. Possibly instead of input may use some class (add class only to necessary input fields).

Is such solution ok?

Seems this is better (shorter) http://jsfiddle.net/NJfL3/2/

Answer 1

you are adding your if condition separately, you need to add it inside your change event, like:

$(".exchange_rate_changed_test1").on("change", function () {
    $('#is_exchange_rate_changed_test1').val(1).change();
    if ($("#is_exchange_rate_changed_test1").val() > 0) {
        alert("Test");    
    }
});