jquery validation plugin help

[o0O0o.o0O0o]

This code is working fine

<script>


$.validator.setDefaults({



submitHandler: function() { 


     $('#signup_form').ajaxForm(); 


     var options = {
        target:        '#result',   // target element(s) to be updated with server response
        beforeSubmit:  showRequest,  // pre-submit callback
        success:       showResponse,  // post-submit callback
        clearForm: true,        // clear all form fields after successful submit
        resetForm: true        // reset the form after successful submit
    };
 



      $('#signup_form').Submit(options);
    
	
	
	
	
	
	
	} 
  });

but when i use this code , my form is submiited even its not validated

<script>


$.validator.setDefaults({



submitHandler: function() { 


     $('#signup_form').ajaxForm(); 


     var options = {
        target:        '#result',   // target element(s) to be updated with server response
        beforeSubmit:  showRequest,  // pre-submit callback
        success:       showResponse,  // post-submit callback
        clearForm: true,        // clear all form fields after successful submit
        resetForm: true        // reset the form after successful submit
    };
 



      $('#signup_form').submit(function(){



$(this).ajaxSubmit(options);


});

}
});