function showHide(argName, imgContId){
    var el = document.getElementById(argName);
    var contId = document.getElementById(imgContId);

    if(el.style.display=="none"){
        contId.style.height = "155px";
        contId.style.overflow = "auto";
	el.style.display = "block";
    }else{
        contId.style.height = "100px";
        contId.style.overflow = "hidden";
        el.style.display = "none";
    }
}

function validate_enquiry_form(){
 valid = true;
 errormessage = '';

 if ( document.contactForm.first_name.value == "" ){
	 errormessage += '- your first name'+"\n";
	 valid = false;
 }

 if ( document.contactForm.last_name.value == "" ){
	 errormessage += '- your last name'+"\n";
	 valid = false;
 }
 if ( document.contactForm.comments.value == "" ){
	 errormessage += '- please insert a comment'+"\n";
	 valid = false;
 }
 if ( ( document.contactForm.email.value == "" ) || (is_email_invalid(document.contactForm.email.value)) ){
 	errormessage += '- a valid email address'+"\n";
 	valid = false;
 }

 if (!valid){
	 alert ( "Please double check your details"+"\n" +"You must supply:"+"\n"+errormessage );
 }
 return valid;
}

function is_email_invalid(){
	var x = document.contactForm.email.value;
	var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
 	if (filter.test(x)){ 
		return false; 
	}else{ 
		return true;
  	}
}