function validate_form_field(FieldName, NotEmpty, Numeric, Alpha, AlphaNumeric, Email, FieldLength){
	
	var Obj = document.getElementsByName(FieldName)[0];
	var err = "";

	if (typeof(Obj) == 'undefined' || Obj == null) {
		return false;
	}

	if (Obj.Value == '') {
		alert("The field is empty");
		return false;
	}

	if(NotEmpty)    {err += FuncNotEmpty(Obj);}
	if(Numeric)     {err += FuncNumeric(Obj);}
	if(Alpha)  		 {err += FuncAlpha(Obj);}
	if(AlphaNumeric){err += FuncAlphaNumeric(Obj);}
	if(Email)       {err += FuncEmail(Obj);}
	if(FieldLength) {err += FuncFieldLength(Obj, FieldLength);}
	if(err != "") {
        	alert(err);
			Obj.value = "";
	      Obj.focus();
	      return false;
	}

	return true;

}

function FuncNotEmpty(Obj){
	var err = "";
	if(!Obj.value){err = "The field is empty.\n";}
	return err;
}

function FuncNumeric(Obj){
	var err = "";
	if (Obj.value.search(/[^0-9-]/) != -1) { err = "You must enter numbers only.\n"; }
	return err;
}

function FuncAlpha(Obj){
	var err = "";
	if (Obj.value.search(/[^a-zA-Z ]/) != -1) {err = "You must enter letters only.\n";}
	//if(!isNaN(Obj.value)){err = "The field is numeric.\n";}
	return err;
}

function FuncAlphaNumeric(Obj){
	var err = "";
	if (Obj.value.search(/[^0-9a-zA-Z]/) != -1) { err = "You must enter numbers and letters only.\n"; }
	return err;
}

function FuncEmail(Obj){
	var err = "";
	var emailFilter=/^.+@.+\..{2,3}$/;
	if (!(emailFilter.test(Obj.value))) { 
		err = "Please enter a valid email address.\n";
	}
	else {
		var illegalChars= /[\(\)\<\>\,\;\:\\\"\[\]]/
	   if (Obj.value.match(illegalChars)) {
	   	err = "The email address contains illegal characters.\n";
	 	}
	}
	return err;
}

function FuncFieldLength(Obj, Len){
	var err = "";
	if(Obj.value.length > Len){err = "The field is longer than the allowed " + Len + " characters.\n";}
	return err;
}