From Ron Spain, this is a calculator app that uses your browser's built in JavaScript interpreter to evaluate expressions, making it both a powerful calculator and a useful tool to help you learn programming. Click on any of the following to evaluate only after you try to figure out what it does. The bottom two are special commands for this app only. 2+2 567+123+987 1234/2+987*6 "hello".charAt(1) "hello".substr(3,2) sin(PI/2) cos(PI) random() floor(random()*6) alert("hello") for(z=0;z<5;++z)alert("Number "+z); cls exit