// Copyright (c) 2009, John Altenmueller -- john@altenmueller.com
// You may freely use and redistribute this code under the terms 
// of the BSD license: http://creativecommons.org/licenses/BSD/

function checkEmail (strng) {
var error="";
if (strng == "") {
   error = "You didn't enter an email address.\n";
}

    var emailFilter=/^.+@.+\..{2,3}$/;
    if (!(emailFilter.test(strng))) { 
       error = "Please enter a valid email address.\n";
    }
    else {
//test email for illegal characters
       var illegalChars= /[\(\)\\<\>\,\;\:\\\"\[\]]/;
         if (strng.match(illegalChars)) {
          error = "The email address contains illegal characters.\n";
       }
    }
return error;    
}
// non-empty textbox

function isEmpty(strng, name) {
var error = "";
  if (strng.length === 0) {
     error = "You did not enter " + name + ".\n";
  }
return error;	  
}

// valid selector from dropdown list

function checkDropdown(choice, name) {
var error = "";
    if (choice === 0) {
    error = "You did not enter " + name + ".\n";
    }    
return error;
}

function checkRadio(radio, name) {
	var error = "";
	var checkvalue = 0;
    for (var i=0, n=radio.length; i<n; i++) {
        if (radio[i].checked) {
            checkvalue = radio[i].value;
            break;
        } 
    }
	if (!(checkvalue)) {
		error = "Please choose " + name + ".\n";
	}
	return error;
}

function checkWholeForm(theForm) {

    var why = "";
	why += isEmpty(theForm.name.value, "name");
    why += checkEmail(theForm.email.value);
	why += checkDropdown(theForm.nationality.selectedIndex, "a nationality");
	why += checkRadio(theForm.term, "a term length");
	why += checkRadio(theForm.school, "a school");
	why += checkRadio(theForm.homestay, "whether you would like info regarding our Homestay Program" );

    if (why != "") {
       alert(why);
       return false;
    }
return true;
}