// JavaScript Document
//function to check empty fields

function isEmpty(strfield1, strfield2, strfield3, strfield4) {


//change "field1, field2 and field3" to your field names

strfield1 = document.forms[0].name.value 

strfield2 = document.forms[0].subject.value

strfield3 = document.forms[0].hearabout.value

strfield4 = document.forms[0].eventlocation.value



  //first name field

    if (strfield1 == "" || strfield1 == null || !isNaN(strfield1) || strfield1.charAt(0) == ' ')

    {

    alert("\"Name\" is a required field.\nPlease amend and retry.")

    return false;

    }



  //last name field 

    if (strfield2 == "" || strfield2 == null || strfield2.charAt(0) == ' ')

    {

    alert("\"Subject\" is a required field.\nPlease amend and retry.")

    return false;

    }



  //phone field 

    if (strfield3 == "" || strfield3 == null || strfield3.charAt(0) == ' ')

    {

    alert("\"How did you hear about us\" is a required field.\nPlease amend and retry.")

    return false;

    }
	
	
	//location field 

    if (strfield4 == "" || strfield4 == null || strfield3.charAt(0) == ' ')

    {

    alert("\"Event Location\" is a required field.\nPlease amend and retry.")

    return false;

    }
	

    return true;

}



//function to check valid email address

function isValidEmail(strEmail){

  validRegExp = /^[^@]+@[^@]+.[a-z]{2,}$/i;

  strEmail = document.forms[0].email.value;



   // search email text for regular exp matches

    if (strEmail.search(validRegExp) == -1) 

   {

      alert('A valid e-mail address is required.\nPlease amend and retry');

      return false;

    } 

    return true; 

}


//function that performs all functions, defined in the onsubmit event handler



function check(form){

if (isEmpty(form.field1)){

 if (isValidEmail(form.email)){

  if (isEmpty(form.field2)){

    if (isEmpty(form.field3)){
		
	if (isEmpty(form.field4)){

		  return true;
		  
				}

			}

	  	}

  	}

}

return false;

}