function getFilePathFromSource(strURL){
	// returns path to file located at URI
	var i = strURL.lastIndexOf("/");
	if(i==-1)
		return strURL
	return strURL.substring(0, i+1);
}
function getFileNameFromSource(strURL){
	// returns filename of file located at URI
	var i = strURL.lastIndexOf("/");
	if(i==-1)
		return strURL;
	return strURL.substring(i+1, strURL.length-1);	
}
function getFileBaseNameFromSource(strURL){
	// returns filename minus extension of file located at URI
	strURL = getFileNameFromSource(strURL);
	var i = strURL.lastIndexOf(".");
	if(i==-1)
		return strURL;
	return strURL.substring(0, i);	
}
function getFileExtensionFromSource(strURL){
	// returns file extension from URI including dot
	var i = strURL.lastIndexOf(".");
	if(i==-1)
		return strURL;
	return strURL.substring(i, strURL.length);	
}