function setOptions(selection) {

	var timeBox = document.appointment.prefTime;
	timeBox.options.length = 0;

	if (selection == 'Tuesday' || selection == 'Thursday'){
		timeBox.options[0] = new Option('Morning', 'Morning');
		timeBox.options[1] = new Option('Afternoon', 'Afternoon');
		timeBox.options[2] = new Option('Evening', 'Evening');
	}else{
		timeBox.options[0] = new Option('Morning', 'Morning');
		timeBox.options[1] = new Option('Afternoon', 'Afternoon');
	}

}



function validate() {
		var form = document.forms['appointment'];
		var i;
		var errorMessage = '';
	
		if(form.fname.value == '') 
			errorMessage = errorMessage + 'Please enter your first name.\n' ;
		if(form.lname.value == '') 
			errorMessage = errorMessage + 'Please enter your last name.\n' ;

// check format of email !
		if(form.email.value == ''){ 
			errorMessage = errorMessage + 'Please enter a valid email address.\n' ;
		}else{
			apos=form.email.value.indexOf("@")
			dotpos=form.email.value.lastIndexOf(".")
				if (apos<1||dotpos-apos<2) 
					errorMessage = errorMessage + 'Please enter a valid email address.\n' ;
		}



// check format of phone number !
		var count=0;
   	 	for (i = 0; i < form.phone.value.length; i++){   
        			var c = form.phone.value.charAt(i);
       			 if ((c < "0") || (c > "9")){
				if (c!="-"){ 
					count=0; // set to zero to account for the break, meaning a letter!
					{break}
				}
				count-=1; // minuses 1 from count to account for the dash!
			}
			count+=1;		
   		}
		if(count != 10) // phone number should have 7 numbers
			errorMessage = errorMessage + 'Please enter a valid phone number.\n' ;	


		if(form.sun.value == '') 
			errorMessage = errorMessage + 'Please indicate if you take any medications.\n' ;
		if(form.sun.value == '') 
			errorMessage = errorMessage + 'Please indicate your recent sun exposure.\n' ;

// display alert or submit

		if(errorMessage != "") 
		{
			alert(errorMessage);
		} else {
			form.submit();
		}
		errorMessage = "";
}