The script uses the average price of Major currencies to show their relative strength. Choose which currencies you wish to see in the format options. The script works based off of RSI so the currency with a higher value is stronger than the currency with the lower value. If for example USD is at 65 and CAD is at 30 then USD is stronger than CAD and buying USDCAD is better idea than selling it.
Sourcecode is open to see.