How to bypass HTML form submission using jQuery (javascript)

Question

I've a simple form

<form action="try.php" method="POST">
    <input id="name" name="name" type="text" placeholder="Name" />
    <input id="btn" name="" type="submit" value="Submit" />
</form>

When I click the submit button, I want to submit the form only if a certain condition is met; and if not, the form will not be submitted (instead show and alert). I do not want to change the markup here. So how do I make it sure that, even though I've provided <form action="try.php" method="POST">, the form doesn't get submitted if the condition is not fulfilled?

I want to do something like the code below.

//jQuery code   
$("#btn").live('click', function(event) {
      if(<condition is true>){
          //Show message
      } else {
         //Submit Form
      }
});

Answer 1

If you don't want to submit the form, you can prevent the default action using preventDefault()

if(<condition is true>){
      event.preventDefault(); 
  }

or return false; It's better to do the former unless you also want to stop the event from bubbling.