Why does an alert redirects my page?

Why does an alert redirects my page?

Why does everytime i put an alert to my ajaxform the page redirects to its
php script? but when I remove the alert the ajax doesn't redirect it. I
don't want my page to redirect to its php script.
$(document).ready(function(){
$("#save").click(function(){
$("#f1").ajaxForm({
alert("Submit Successful!");
});//ajaxform
});
});