function isEmptyString(str) {
	var strVal = document.forms.myForm[str].value;
	if (0 < strVal.length) return 0;
	if (0 >= strVal.length) return 1;
	if (' ' == strVal.charAt(0)) return 1;
	if ('\n' == strVal.charAt(0)) return 1;	
	if ('\t' == strVal.charAt(0)) return 1;	
   return 0;
}
ERROR_EMPTY_STRING="Please enter your name at the top of the form.";
ERROR_EMPTY_STRING_2="Please enter a phone number, day or evening.";
function OnSubmit(){
	if( isEmptyString("ch1")){
		alert(ERROR_EMPTY_STRING);
		return false;
	}else if( isEmptyString("ch3") && isEmptyString("ch4")){
		alert(ERROR_EMPTY_STRING_2);
		return false;
	}
	return true;
}