// navigation rollovers
function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}
function changeImages() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}
var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		GTsymposium_nav_01_over = newImage("../images/GTsymposium_nav_01_over.gif");
		GTsymposium_nav_02_over = newImage("../images/GTsymposium_nav_02_over.gif");
		GTsymposium_nav_03_over = newImage("../images/GTsymposium_nav_03_over.gif");
		GTsymposium_nav_04_over = newImage("../images/GTsymposium_nav_04_over.gif");
		preloadFlag = true;
	}
}

// form valiation
function MM_findObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}
function MM_validateForm() { //v4.0
  var i,p,q,nm,test,num,min,max,errors='',args=MM_validateForm.arguments;
  for (i=0; i<(args.length-2); i+=3) { test=args[i+2]; val=MM_findObj(args[i]);
    if (val) { nm=val.name; if ((val=val.value)!="") {
      if (test.indexOf('isEmail')!=-1) { p=val.indexOf('@');
        if (p<1 || p==(val.length-1)) errors+='- '+nm+' must contain an e-mail address.\n';
      } else if (test!='R') { num = parseFloat(val);
        if (isNaN(val)) errors+='- '+nm+' must contain a number.\n';
        if (test.indexOf('inRange') != -1) { p=test.indexOf(':');
          min=test.substring(8,p); max=test.substring(p+1);
          if (num<min || max<num) errors+='- '+nm+' must contain a number between '+min+' and '+max+'.\n';
    } } } else if (test.charAt(0) == 'R') errors += '- '+nm+' is required.\n'; }
  } if (errors) alert('The following error(s) occurred:\n'+errors);
  document.MM_returnValue = (errors == '');
}

function validate (form) {
// define question groups
var groups = new Array (
new Array ("A", "Event", false),
new Array ("B", "Payment_Method", false)
);

    // run the check that's already defined
    MM_validateForm ('First_Name','','R',
					'Last_Name','','R',
					'Organization','','R',
					'Address1','','R',
					'City','','R',
					'State_Province','','R',
					'Zip_Postalcode','','R',
					'Bus_Phone','','R',
					'Bus_Fax','','R',
					'Email','','RisEmail');
    if (!document.MM_returnValue) return false;

    // loop on all form elements
    for (var i = 0; i < form.elements.length; i++) {
        var elem = form.elements[i];

        // skip those which aren't a checkbox or a radio box
        if (elem.type != "checkbox" && elem.type != "radio") continue;

        // for every element, check if it belongs in a group
        for (var j = 0; j < groups.length; j++)
            if (elem.name.charAt(0) == groups[j][0] && elem.checked)
                // if so, and if it's checked, mark that group as OK
                groups[j][2] = true;
    }

    // if any groups remain which aren't flagged OK, abort
    for (var j = 0; j < groups.length; j++)
        if (!groups[j][2]) {
            alert ("Please select " + groups[j][1]);
            return false;
        }

    // otherwise proceed with form submission
    return true;
}