//get window width
function getWidth() {
  var myWidth = 0;
  if( typeof( window.innerWidth ) == 'number' ) {
    //Non-IE
    myWidth = window.innerWidth;
  } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
    //IE 6+ in 'standards compliant mode'
    myWidth = document.documentElement.clientWidth;
  } else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
    //IE 4 compatible
    myWidth = document.body.clientWidth;
  }  
  return myWidth;
}

//get window height
function getHeight() {
  var myHeight = 0;
  if( typeof( window.innerHeight ) == 'number' ) {
    //Non-IE
    myHeight = window.innerHeight;
  } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
    //IE 6+ in 'standards compliant mode'
    myHeight = document.documentElement.clientHeight;
  } else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
    //IE 4 compatible
    myHeight = document.body.clientHeight;
  }
  return myHeight;
}

//validate popup form
function CheckForm(f,elem) {
	if (f.email.value == "") {
		alert("Please enter your email address.");
		f.email.focus();
		return false;
	} else { 
		var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
		var address = f.email.value;
		if(reg.test(address) == false) {
			alert('Invalid email address');
			return false;
		} else { 
			deactivateBox(elem);
		}
	}
	return true;
}