ecma262

I don't find anything about my question here on MDC or the ECMAscript specifications. Probably somebody knows a more 'hacky' way to solve this. I'm calling "use strict" on every javascript file in my environment. All my files start like this (function(win, doc, undef) { "use strict"; // code & functions }(window, window.document)); Now, I have a custom function which handles errors. That functions uses the .caller property to provide a context stack trace . Looks like this: var chain = (function() { var _parent = _error, _ret = ''; while( _parent.caller ) { _ret += ' -> ' + _parent.caller.name

Okay, we all know what the valid left-hand-side expressions are. Kind of.* But, looking at the definition from the ECMA-Script standard , I'm very confused: LeftHandSideExpression : NewExpression CallExpression Is that just an error in the definition, or am I getting something wrong here? I mean, doesn't that actually mean that new Object = 1; // NewExpression AssignmentOperator PrimaryExpression function () { return foo; }() = 1;// CallExpression AssignmentOperator PrimaryExpression are supposed to be valid assignment expressions? * From my humble understanding, this would make much more

Looking into javascript types I'm trying to find out what the maximum storage size for some data types are. For instance, I set up a quick recursive algo to increase var size till the browser crashes, which ends up being somewhere close to 128mb (or maybe it's 256) for strings on my existing version of chrome. I've been doing it the painful way because I couldn't find any specs on this, but constant browser crashes make this a painful trial (try catch seems useless for some reason with this particular issue). I'm looking for information about maximum storage size for the other types also

Can someone tell me since which ECMA version the IN operator is available and which browsers (versions) support it ? Explanation: The IN-operator can be used like the following: var myObject = { Firstname: 'Foo', Lastname: 'Bar' }; if('Lastname' in myObject){ // Lastname is an attribute of myObject } It is defined in ECMAScript 3rd edition . It is available in IE 5.5+ and all in-use versions of Firefox, Chrome, Opera and Safari. You can use it safe in the knowledge that it will work. You should err on the side of caution when using it to check event support. All implementations except older

I'm seeing posts about a 'new' Object.create that makes enumeration configurable. However, it relies on a Object.defineProperty method. I can't find a cross browser implementation for this method. Are we stuck writing for the old Object.create? I can't write things that won't work in IE6/7. There are several things that you can't emulate from the ECMAScript 5 Object.create method on an ECMAScript 3 environment. As you saw, the properties argument will give you problems since in E3-based implementations there is no way to change the property attributes. The Object.defineProperty method as

Any idea why JSON left out NaN and +/- Infinity? It puts Javascript in the strange situation where objects that would otherwise be serializable, are not, if they contain NaN or +/- infinity values. Looks like this has been cast in stone: see RFC4627 and ECMA-262 (section 24.3.2, JSON.stringify, NOTE 4, page 507 at last edit): Finite numbers are stringified as if by calling ToString(number) . NaN and Infinity regardless of sign are represented as the String null . Infinity and NaN aren't keywords or anything special, they are just properties on the global object (as is undefined ) and as such