I want to prevent form submission when there is no input in the text boxes but the form submits even when the input is empty. How do I fix this?

1. 
   
2. var input = $("#zip").val();
3. var input1 = $("#phone").val();
4. 
   
5. if ( $.trim(input).length == 0 || $.trim(input1).length == 0 ){
6. event.preventDefault();
7. }

1. <input type="text" size="30" id="zip" name="zip"><br />
2. <input type="text" size="30" id="phone" name="phone">