function formcheck() // onsubmit="return formcheck()" in form tag of html page to activate script

{
	
	var a = 0;
	var missingfield = new Array('', '', '', '');


	if ( document.forms['contactform'].elements['Name'].value == "")

		{		
		a++;
		missingfield[0] = ": Name\n";
		}

	if ( document.forms['contactform'].elements['Telephoneday'].value == "")

		{
		a++;
		missingfield[1] = ": Daytime telephone number\n";
		}

	if ( document.forms['contactform'].elements['Telephoneevening'].value == "")

		{
		a++;
		missingfield[2] = ": Evening telephone number\n";
		}



	if ( document.forms['contactform'].elements['Email'].value == "" ||
		 document.forms['contactform'].elements['Email'].value.indexOf("@") == -1)

		{
		a++;
		missingfield[3] = ": E-mail address\n";
		}

		
	if ( a== 0)
		{
		return true;
		}

	else
		{
		window.alert("Please check that the following fields\nhave been correctly filled in:\n\n" 
						+ missingfield[0] 
						+ missingfield[1]
						+ missingfield[2]
						+ missingfield[3]);
		return false;
		}
}