What's the difference between JavaScript and JScript?

Solution 1:

Just different names for what is really ECMAScript. John Resig has a good explanation.

Here's the full version breakdown:

• IE 6-7 support JScript 5 (which is equivalent to ECMAScript 3, JavaScript 1.5)
• IE 8 supports JScript 6 (which is equivalent to ECMAScript 3, JavaScript 1.5 - more bug fixes over JScript 5)
• Firefox 1.0 supports JavaScript 1.5 (ECMAScript 3 equivalent)
• Firefox 1.5 supports JavaScript 1.6 (1.5 + Array Extras + E4X + misc.)
• Firefox 2.0 supports JavaScript 1.7 (1.6 + Generator + Iterators + let + misc.)
• Firefox 3.0 supports JavaScript 1.8 (1.7 + Generator Expressions + Expression Closures + misc.)
• The next version of Firefox will support JavaScript 1.9 (1.8 + To be determined)
• Opera supports a language that is equivalent to ECMAScript 3 + Getters and Setters + misc.
• Safari supports a language that is equivalent to ECMAScript 3 + Getters and Setters + misc.

Solution 2:

As far as I can tell, two things:

1. ActiveXObject constructor
2. The idiom f(x) = y, which is roughly equivalent to f[x] = y.