javascript object in anonymous function tag trigger

Question

i have made an tag trigger function inside an anonymous function , here it is :

(function(){
  var getElement = {
    getElem: function(element , elemInterval){
      if(document.getElementsByTagName('div')[0].onload){
        element = document.getElementsByTagName('div')[0];
        clearInterval(elemInterval);
        element.innerHTML = ' content changed. ';
      }
    }
  }
  var element , elemInterval;
  elemInterval = setInterval(getElement.getElem(element , elemInterval) , 1000);
})();

what it got to do is to call a function as many time as it needs every one second and check if the first div as been loaded , than it save the element port to the "element" var and change the content of the div.

this seems to not work , what's the problem here?

pimvdb · Accepted Answer · 2011-10-15 20:37:14Z

1

You're calling it directly and passing the result value to setInterval, which is undefined.

What you probably want is passing a function to setInterval, which in turn will call getElem:

elemInterval = setInterval(function() {
                               getElement.getElem(element , elemInterval);
                           }, 1000);

answered Oct 15, 2011 at 20:37

pimvdb

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4 Comments

homerun Over a year ago

I've tried it but it actually doing nothing , here is a live example : jsfiddle.net/NGnEd

pimvdb Over a year ago

@Mor Sela: That's because of your if clause. Why do you check for onload? jsfiddle.net/NGnEd/1

homerun Over a year ago

that's awesome man ! i though that the onload should give me true if it have been loaded , but i guess i was wrong , thank men.

pimvdb Over a year ago

@Mor Sela: No, you're checking whether the element has an onload="..." attribute, which is not really meaningful here.

duri · Accepted Answer · 2011-10-15 20:36:26Z

1

You call the function immediately and pass undefined (its return value) as the first argument of setInterval. Learn how closures work.

elemInterval = setInterval(function() {
    getElement.getElem(element , elemInterval);
}, 1000);

answered Oct 15, 2011 at 20:36

duri

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1 Comment

homerun Over a year ago

I've tried it but it actually doing nothing , here is a live example : jsfiddle.net/NGnEd

cthulhu · Accepted Answer · 2011-10-15 20:38:17Z

0

The problem is most likely that of scope - the getElem function is contained in a var, which is contained in the function block (which has a scope of its own as well). Interval functions need to be accessible in the global scope.

I'm not able to test this right now, but iirc, this would work:

var something = (function(){
  var getElement = {
    getElem: function(element , elemInterval){
      if(document.getElementsByTagName('div')[0].onload){
        element = document.getElementsByTagName('div')[0];
        clearInterval(elemInterval);
        element.innerHTML = ' content changed. ';
      }
    }
  }
  var element , elemInterval;
  elemInterval = setInterval(something.getElement.getElem(element , elemInterval) , 1000);
  return getElement;
})();

But that's a high level of indirection, you might want to avoid containing your function in another nested function.

answered Oct 15, 2011 at 20:38

cthulhu

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2 Comments

homerun Over a year ago

why you return this object in the end?

cthulhu Over a year ago

Because that's what gets assigned to 'var something' - without the return, something contains the function definition instead of the getElement object with the getElem method.

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