使用 jQuery 更改输入文本值（如果它是 NaN）

Question

I want to change value of textbox to -999, if it is having a value of NaN. I have written some code but it is not working, please suggest me what I need to change in this.

 if($('input[name="tt10"]').val() === NaN) { $('input[name="tt10"]').val('-999'); }

 <input name='tt10' value='NaN'> <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>

Answer 1

You need to call .val() to get the value of the input. And since the value is a string, you need to compare it with a string.

 if($('input[name="tt10"]').val() === 'NaN') { $('input[name="tt10"]').val('-999'); };

 <input name='tt10' value='NaN'> <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>

Answer 2

You have to use .val() to get value from input field .
Like this:

$('input[name="tt10"]').val()

And with that value now, you can check if value of input is NaN or not:

if($('input[name="tt10"]').val() === 'NaN') {
    $('input[name="tt10"]').val('-999');
};

For more information you can visit official documentation .