How to prevent “A script on this page is causing Internet Explorer to run slowly” without changing MaxScriptStatements in the registry?

Question

We are using Bing and/or Google javascript map controls, sometimes with large numbers of dynamically alterable overlays.

I have read http://support.microsoft.com/kb/175500/en-us and know how to set the MaxScriptStatments registry key.

Problem is we do not want to programmatically set this or any other registry key on users' computers but would rather achieve the same effect some other way.

Is there another way?

Answer 1

Hardly anything you can do besides making your script "lighter". Try to profile it and figure out where the heaviest crunching takes place, then try to optimize those parts, break them down into smaller components, call the next component with a timeout after the previous one has finished and so on. Basically, give the control back to the browser every once in a while, don't crunch everything in one function call.

Answer 2

Generally a long running script is encountered in code that is looping.

If you're having to loop over a large collection of data and it can be done asynchronously--akin to another thread then move the processing to a webworker(http://www.w3schools.com/HTML/html5_webworkers.asp).

If you cannot or do not want to use a webworker then you can find your main loop that is causing the long running script and you can give it a max number of loops and then cause it to yield back to the client using setTimeout.

Bad: (thingToProcess may be too large, resulting in a long running script)

function Process(thingToProcess){     
    var i;
    for(i=0; i < thingToProcess.length; i++){
        //process here
    }
}

Good: (only allows 100 iterations before yielding back)

function Process(thingToProcess, start){    
    var i;
    if(!start) start = 0;
    for(i=start; i < thingToProcess.length && i - start < 100; i++){
        //process here
    }
    if(i < thingToProcess.length) //still more to process
        setTimeout(function(){Process(thingToProcess, i);}, 0);
}

Both can be called in the same way:

Process(myCollectionToProcess);