javascript to find memory available

Question

Let's make it immediately clear: this is not a question about memory leak! I have a page which allows the user to enter some data and a JavaScript to handle this data and produce a result. The JavaScript produces incremental outputs on a DIV, something like this:

(function()
{
   var newdiv = document.createElement("div");
   newdiv.innerHTML = produceAnswer();
   result.appendChild(newdiv);
   if (done) {
      return;
   } else {
      setTimeout(arguments.callee, 0);
   }
})();

Under certain circumstances the computation will produce so much data that IE8 will fail with this message:

not enough storage when dealing with too much data

The question is: is there way I can work out how much data is too much data?

as I said there is no bug to solve. It's a genuine out of memory because the computation requires to create too many html elements.

My idea would be to run a function before executing the computation to work out ahead if the browser will succeed. But to do so, in a generic way, I think I need to find the memory available to my browser.

Any suggestion is welcome.

Answer 1

I suspect having a 0 timeout delay is the problem - it's trying to re-run instantly. Try increasing this.

Answer 2

Have a play with this...

document.write(performance.memory.jsHeapSizeLimit+'<br><br>');
document.write(performance.memory.usedJSHeapSize+'<br><br>');
document.write(performance.memory.totalJSHeapSize);

Answer 3

A loop will use less memory than recursion.

   do
   {
     var newdiv = document.createElement("div");
     newdiv.innerHTML = produceAnswer();
     result.appendChild(newdiv);
   } while (!done);

You could also put some upper limit on the number of answers produced.

   var answerCount = 0;
   do
   {
     var newdiv = document.createElement("div");
     newdiv.innerHTML = produceAnswer();
     result.appendChild(newdiv);
   } while (!done && answerCount++ < 1000);

Answer 4

Javascript (in the browser) is run in a sandbox, which means that it is fenced-off from accessing things that could cause security issues such as local files, system resources etc - so no, you can't detect memory usage.

As the other answers state, you can make the task easier for the browser by pausing between implementations or using less resource-intensive code, but every browser has its limits.