function getExt(str) {
	arr=str.split(".");

	var ext=arr[arr.length-1];

	return ext;
}

function isImage(fn) {
	ext=getExt(fn);

	E=ext.toUpperCase();

	if (E=="JPG" || E=="JPEG" || E=="PNG" || E=="GIF" || E=="BMP") return true;

	return false;
}

function URLEncode(str)
{
// The Javascript escape and unescape functions do not correspond
// // with what browsers actually do...
	var SAFECHARS = "0123456789" +					// Numeric
		"ABCDEFGHIJKLMNOPQRSTUVWXYZ" +	// Alphabetic
		"abcdefghijklmnopqrstuvwxyz" +
		"-_.!~*'()";					// RFC2396 Mark characters
	var HEX = "0123456789ABCDEF";

	var plaintext = str;
	var encoded = "";

	c=plaintext.length;
	for (var i = 0; i < c; i++ ) {
		var ch = plaintext.charAt(i);

		if (ch == " ") {
			encoded += "+";				// x-www-urlencoded, rather than %20
		} else if (SAFECHARS.indexOf(ch) != -1) {
			encoded += ch;
		} else {
			var charCode = ch.charCodeAt(0);
			if (charCode > 255) {
				alert( "Unicode Character '" + ch + "' cannot be encoded using standard URL encoding.\n" +
					"(URL encoding only supports 8-bit characters.)\n" +
					"A space (+) will be substituted." );
				encoded += "+";
			} else {
				encoded += "%";
				encoded += HEX.charAt((charCode >> 4) & 0xF);
				encoded += HEX.charAt(charCode & 0xF);
			}
		}
	} // for

	return encoded;
}

function URLDecode(str)
{
	// Replace + with ' '
	// Replace %xx with equivalent character
	// Put [ERROR] in output if %xx is invalid.
	var HEXCHARS = "0123456789ABCDEFabcdef"; 
	var encoded = str;
	var plaintext = "";
	var i = 0;

	c=encoded.length;
	while (i < c) {
		var ch = encoded.charAt(i);

		if (ch == "+") {
			plaintext += " ";
			i++;
		} else if (ch == "%") {
			if (i < (encoded.length-2) 
			&& HEXCHARS.indexOf(encoded.charAt(i+1)) != -1 
			&& HEXCHARS.indexOf(encoded.charAt(i+2)) != -1 ) {
				plaintext += unescape( encoded.substr(i,3) );
				i += 3;
			} else {
				alert( 'Bad escape combination near ...' + encoded.substr(i) );
				plaintext += "%[ERROR]";
				i++;
			}
		} else {
			plaintext += ch;
			i++;
		}
	} // while

	return plaintext;
}