How to check if checkbox is checked?

Is it the correct way to check if the check box is tick?

        <input type="checkbox" class="custom-control-input check" name="A" id="A" value= "<?php if(isset($resDtl[0]) && $resDtl[0]->A==1) echo "checked"; ?>" />
        <label class="custom-control-label" for="A">A</label>

JavaScript

var obj={};

      $(".check").each(function(){
            var name = this.name;
            if ($("[name='" + name + "']:checked").val() == true)
                obj[name] = true;
            else
                obj[name] = "";
        })

        return obj;

coder222

5 years ago

Level 1

For checkbox input the important attributes are:

<input type="checkbox" name="cb_name" value="cb_val" checked="checked" />

When the form is submitted, the value of cb_name will be cb_val whatever its value if the checkbox is checked, if it is not checked then cb_val will not even be set.

Now you can figure out where to put your if(isset(...)) code, instead of in the value attribute it should be outside of it.

<input type="checkbox" name="cb_name" value="1" <?php if ($cb_name == 1) echo 'checked="checked"' ?> />

or if you're using laravel blade template:

<input type="checkbox" name="cb_name" value="1" @if($cb_name == 1) checked="checked" @endif />

1 like

jlrdw

5 years ago

Level 75

I usually:

 var mycheck = ($("#yourcheck").prop("checked") == true ? '1' : '0');

1 like

dev_nope

5 years ago

Level 10

In vanilla JavaScript you can make use of the checked property of the "checkbox" JavaScript element object. See examples on MDN.

Given you have the following HTML:

<label>
  <input type="checkbox" id="is_admin" name="is_admin" value="1">
  Is Admin
</label>

Then in JavaScript you can do this:

const isAdminCheckbox = document.querySelector('#is_admin');

console.log(isAdminCheckbox.checked ? 'Is Checked' : 'Is Unchecked');

You can check out this codepen example as well 👍

Like @coder222 mentioned, when the checkbox is unchecked and you're POST-ing the form, then that checkbox field won't even be present in PHP's $_POST array. One little trick I like to use to make sure the checkbox field is always present when the form is POST-ed (I've learned that from other people online), is placing a hidden input with the same name attribute and a default value before the checkbox itself in HTML, like so:

<input type="hidden" name="is_admin" value="0">
<input type="checkbox" id="is_admin" name="is_admin" value="1">

Result:

form POST-ed and is_admin is checked: $_POST['is_admin'] will be 1
form POST-ed and is_admin is unchecked: $_POST['is_admin'] will be 0

1 like

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