function GetFileExtension(fileName)
{
	// Intitialize variables
	var fileExtension = "";
	var dotPosition = 0;
	
	// Check the filename length
	if (fileName.length != 0)
	{
		// Get the position of the last '.'
		dotPosition = fileName.lastIndexOf(".");
		
		if (dotPosition != -1)
		{
			// Get the file extension
			fileExtension = fileName.substr(dotPosition, fileName.length);
		}
	}
	
	// Return result
	return fileExtension;
}

function IsJPEG(fileName)
{
	// Initialize variable
	var validJPEG = false;
	var fileExtension = GetFileExtension(fileName);
	
	// Check if it is a valid jpeg extension
	if (fileExtension == ".jpg" || fileExtension == ".jpeg")
	{
		validJPEG = true;
	}
	
	// Return result
	return validJPEG;
}

function CheckFileExtension(fileName)
{
	if (!IsJPEG(fileName))
	{
		alert("Er kunnen alleen JPG foto's ge-upload worden");
	}
}