function validate(){

var validationRule = new RegExp(/^[^@]+@([-\w]+\.)+[A-Za-z]{2,4}$/);

var nameField =  document.forms["contact"].name.value;
var emailField =  document.forms["contact"].email.value;
var subjectField =  document.forms["contact"].subject.value;
var enquiryField =  document.forms["contact"].enquiry.value;

    if( nameField.length == 0 ){
      alert("Please enter your name!");
      return false;
    }

    if( emailField.length == 0 ){
      alert("Please enter your email address!");
      return false;
    }

    if( !validationRule.test(emailField) ){
      alert("Please enter a valid email address!");
      return false;
    }

    if( subjectField.length == 0 ){
      alert("Please enter your subject!");
      return false;
    }

    if( enquiryField.length == 0 ){
      alert("Please enter your enquiry!");
      return false;
    }

document.forms["contact"].submit();

}