Question: *Textbox refers to `<input type="text">` in this question.*

For each textbox with a given class i would like to check if the value equals `''`, and if it does I want to make the value `'0'`. I would like to do this as soon as the page is loaded.

This is the closest I've got now:

```
$(document).ready(function() {
  if ($('.myclass').val() == '') $('.myclass').val('0');
})

```

The problem here is that this code will give all my textboxes (with `class="myclass"`) the value `'0'` as soon as one of them is empty. I know this is the expected behaviour given the code I use now, but I'm pretty new to jQuery and I haven't really got the hang of the selectors yet. How would I solve this? Do I need to create a separate function to do the check on one element and then call that for each of the elements that apply to the selector? If so, how would I do this?

Answer: 
This might be the simplest answer:

```
$("input.myclass[value=]").val("0");

```

Only elements with no value get selected. This works because the value attribute reflects the text the user put in.
```
$(document).ready( function() {
  $('input:checkbox').each( function() {
    // check the val
    if( $(this).val()=='')
      // do something
  });
});

```