function changeVisibility (objectID, newVisibility) {
	var styleObject = getStyleObject(objectID);
	if (styleObject) {
		styleObject.visibility = newVisibility;
		return true;
	} else {
		return false;
	}
} // changeVisibility

function getStyleObject (objectId) {
	// cross-browser function to get an object's style object given its id
  if(document.getElementById && document.getElementById(objectId)) {
	// W3C DOM
		return document.getElementById(objectId).style;
  } else if (document.all && document.all(objectId)) {
	// MSIE 4 DOM
		return document.all(objectId).style;
  } else if (document.layers && document.layers[objectId]) {
	// NN 4 DOM.. note: this won't find nested layers
		return document.layers[objectId];
  } else {
		return false;
  }
} // getStyleObject

function getQueryVariable (variable) {
	var query = window.location.search.substring(1);
	var vars = query.split("&");
	for (var i=0;i<vars.length;i++) {
		var pair = vars[i].split("=");
		if (pair[0] == variable) return pair[1];
	}
}

function numbersonly (myfield, e, dec) {
	var key;
	var keychar;
	
	if (window.event)
	   key = window.event.keyCode;
	else if (e)
	   key = e.which;
	else
	   return true;
	   
	keychar = String.fromCharCode(key);
	
	if ((key==null) || (key==0) || (key==8) || 
		(key==9) || (key==13) || (key==27) )
	   return true;
	
	else if ((("0123456789").indexOf(keychar) > -1))
	   return true;
	
	else if (dec && (keychar == "."))
	   {
	   myfield.form.elements[dec].focus();
	   return false;
	   }
	else
	   return false;
}

function whatIsProveItImg (src) {
	window.open('whatisimg.html?image=' + src, 'whatisproveit', 'menubars=false, scrollbars=auto, width=780, height=590');
}