Simple JavaScript Checkbox Validation

Question

I usually work with PHP so sadly don\'t have some basic JS principles down. This is all I want to accomplish--I\'ve seen many posts on this topic but they are usually beyon

Answer 1

You could use:

 if(!this.form.checkbox.checked)
{
    alert('You must agree to the terms first.');
    return false;
}

(demo page).

• Returning false from an inline event handler will prevent the default action from taking place (in this case, submitting the form).
• ! is the Boolean NOT operator.
• this is the submit button because it is the element the event handler is attached to.
• .form is the form the submit button is in.
• .checkbox is the control named "checkbox" in that form.
• .checked is true if the checkbox is checked and false if the checkbox is unchecked.