function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      oldonload();
      func();
    }
  }
}


function prepareFormValidation () {
	document.forms['frmFreeEstimate'].onsubmit = function () {
		return validate()
	}
}

function validate() {

	validForm = true;
	firstError = null;

	var x = document.forms['frmFreeEstimate'].elements;

	if (x['your_name'].value == '') {
	    writeError(x['your_name'],'Please enter your name!');
	}

	if (x['your_email'].value == '') {
	    writeError(x['your_email'],'Please enter an email address!');
	}

	if (x['daytime_telephone_number'].value == '') {
	    writeError(x['daytime_telephone_number'],'Please enter a daytime telephone number!');
	}


	if(!validForm) return false;

	return true;
}

addLoadEvent(prepareFormValidation);