Question

If the browser is executing JavaScript on a web page and it encounters invalid JavaScript
(e.g. somerandomthingy;) Does execution of JavaScript stop at that point, or do async operations continue. Also do JavaScript events still work (e.g. onclick).

Answer 1

Yes, except asynchronous ones. http://jsfiddle.net/pimvdb/R4dfJ/3/

DIY:

var a = 1, b, c;

setTimeout(function() {
    b = 2;
    console.log('Running', a, b, c);
}, 1000);

somerandomthingy;

c = 3;

Uncaught ReferenceError: somerandomthingy is not defined

Running 1 2 undefined

So:

• a and b have been set
• c has not been set
• Timeout still occurs

As for ‘does onclick still work’ – well, if the handler is set in code that runs (i.e. before an error) it does; in case it is put after error code it won’t bind the handler so events won’t work.