Question

I’m using Ajax to test if the Username on a Register form is too short.

Right now it just does this:

if (str.length<6)
  { 
  document.getElementById("txtHint").innerHTML="Too short";
  return;
  } 

How do I add an action above that doesn’t let the user submit?

<form action="/insert/insert-user.php" method="post">
    <input type="text" name="user"  onkeyup="showHint(this.value)"/>

Answer 1

You may try adding a form name and onsubmit event to your form.

<form name="formName"action="/insert/insert-user.php" method="post" onsubmit="validate()">

function validate() {
    if (document.formName.user.value.length < 7) {
        // Display your message in your division 
         return false;
    }
}

You must also repeat the check in php since the user may have Javascript disabled and for security measure:

if ($_POST['your_submit_button']) {
    if (strlen($_POST['user']) < 7) {
        $submit = false;
        die ("<div style='color: red;'>Too short</div>"); 
    }
}