Checkbox checked validation using JavaScript
You can check whether a checkbox is checked or not using checkbox_elemnt.checked attribute. Here is an example: See the Pen single checkbox validation by Prasanth (@prasanthmj) on CodePen. Here is the JavaScript code for easy reference: function validateForm(form) { console.log("checkbox checked is ", form.agree.checked); if(!form.agree.checked) { document.getElementById('agree_chk_error').style.visibility='visible'; return false; } else { document.getElementById('agree_chk_error').style.visibility='hidden'; return true; } }
How to do multiple checkbox validation in Javascript
Checkboxes can be used as a single checkbox (like an on-ff switch) or as a group of checkboxes where the user can select one or more options. How do we do validations when you have multiple checkboxes? Here are some samples. At least one checkbox should be checked (Required validation) See the Pen Multiple checkbox validation by Prasanth (@prasanthmj) on CodePen. In the validation code, we extract the FormData object from the form element.
HTML Form Checkbox with required validation
The code below shows how to create a single checkbox with “required” validation. Make sure you have not selected the checkbox and then press the submit button to see the error message. See the Pen Checkbox required validation by Prasanth (@prasanthmj) on CodePen. Required Validation for a group of checkboxes Although the HTML5 ‘required’ validation will work fine with Single checkboxes, there is no HTML5 validation for a group of checkboxes.