check checkbox if another checkbox is checked

Question

I want the checkbox with the value 2 to automatically get checked if the checkbox with the value 1 is checked. Both have the same id so I can't use getElementById. html: ``` 1
2 ``` I tired: ``` var chk1 = $("input[type="checkbox"][value="1"]"); var chk2 = $("input[type="checkbox"][value="2"]"); if (chk1:checked) chk2.checked = true; ```

Accepted Answer

You need to change your HTML and jQuery to this:

```
var chk1 = $("input[type='checkbox'][value='1']");
var chk2 = $("input[type='checkbox'][value='2']");

chk1.on('change', function(){
    chk2.prop('checked',this.checked);
});
```

`id` is unique, you should use class instead.

Your selector for `chk1` and `chk2` is wrong, concatenate it properly using `'` like above.

Use change() function to detect when first checkbox checked or unchecked then change the checked state for second checkbox using prop().

Fiddle Demo

check checkbox if another checkbox is checked

Solution

Problem

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