weird IE 7 javascript problem

I have this javascript code working in firefox, chrome, and safari

for (idx in all_auction_ids){
    alert(all_auction_ids[idx]);
};

for the above, instead of getting the values in all_auction_ids, the first value I get is text of type function that looks like a for loop!

But if I run the code below, it works fine.

for (idx=0;idx<all_auction_ids.length;idx=idx+1){
    alert(all_auction_ids[idx]);
};

edit: updates

I did some debugging and found out that, adding Orbited and stomp.js is probably doing something with the array!

for now i am using Tracker1's suggestion jquery's $.each.

more info: http://groups.google.com/group/orbited-users/browse_thread/thread/7fd658cfb166e9fa

array with the problem http://bayimg.com/fAnhaAaBb

array without the problem http://bayimg.com/FaNhEAabb

From stackoverflow

• JavaScript's for/in construct is traditionally for iterating over object member names, not array indices. The more forward-thinking browsers have added features like hidden properties to help cases like Array enumerate in the way you would expect, but IE stilll does it the old-school way and gives you Object members like the 'toString' method when you use for/in over an Array.

  The indexed-for is still the canonical JavaScript array loop. (Although you probably mean 'for (var idx=...', and 'idx++' is more common.)

  Prestaul : I agree that the "for(var i = 0..." method is preferable for an indexed array, but IE has always supported the "for(var i in..." iterator because an Array object is just an object with an auto-increment feature after all.

  mark : yeah!, IE should support for in , this is weird right?

  Prestaul : @kevin: Not "should", DOES! There is something else going on here and I don't think we've been given enough detail yet...

  Prestaul : @bobince, when was the last time you saw IE return 'toString' using for/in on an Array? I don't think I've ever seen this, going back to IE5...

  bobince : Hmm, you're right, seems toString has been gone for a while. However there is also the chance something could have added to Array.prototype... actually if you're running one of those JavaScript frameworks that just loves spraying methods into prototypes it's a certainty.

  Prestaul : @bobince, that is certainly true. @mark (@kevin?), are you using any javascript libraries (e.g. jQuery, Prototype.js, Mootools, something homegrown)?

• I agree with @bibince that you probably should be using the "for(var i = 0..." syntax, but there is no reason that the syntax you chose should not work unless you have done something strange in your creation of all_auction_ids. How are you initializing your array?

  Arrays in JavaScript are just objects with a special auto-incrementing feature, but in reality they are not much different that an anonymous object. Try this in Firebug:

  var a = ['a','b','c'];
  a.d = 'd';
  for(var i in a) console.log(i, a[i]);
  

  or paste this into your address bar in IE and hit enter:

  javascript:var a = ['a']; a.d = 'd'; for(var i in a) alert(a[i]); alert(a.length);
  

  EDIT:

  I doubt this is your problem, but do you have the same problem if you use:

  var all_auction_ids = [];
  

  rather than

  var all_auction_ids = new Array();
  

  If that doesn't help then could you post a little more of your code to give us a better idea of how you are populating all_auction_ids?

  mark : Prestaul: I have this problem only in IE (both 7 and 8) not in firefox. all_auction_ids = new Array(); and i add data to it this way. all_auction_ids.push(id); it works well in safari/ffox

  Prestaul : @kevin: I've updated my post. I think that I would start by changing the declaration to var all_auction_ids = []; and removing the semi-colon after the for block. That probably isn't your problem but we might need more detail to figure it out.

  Prestaul : Also, you might add a "var"... i.e. "for(var idx in..."

• It's worth noting that some libraries such as prototype.js extend Array, so that they have additional properties beyond the internal indexes. This breaks for x in y notation beyond, as other mentioned, that IE will iterate properties. for i=0...i++ is preferred.

  Also worth noting is jQuery, prototype and others offer a .each(fn) notation that I actually prefer.

• This topic on the YUI blog is germane to your problem.

• I've been having similar problems lately creating "select all / clear all" buttons for lists of checkboxes. In Firefox and Chrome they work fine, but in IE7/8 they don't. I'm not using any frameworks or external libraries, all the JavaScript is my own, it's fairly straightforward stuff, and there isn't much of it. I build the array of input elements using getElementsByTagName, then loop through:

  var allClearInputs = document.getElementsByTagName("input");
  for(ac=0;ac<allClearInputs.length;ac=ac+1){
      if(allClearInputs[ac].id){
          var thisNameArr = allClearInputs[ac].id.split("-");
          var thisName = thisNameArr[0];
          if(thisName == checkName){
              if((actionType == 'all' && allClearInputs[ac].checked == false) || (actionType == 'clear' && allClearInputs[ac].checked == true)){
                  allClearInputs[ac].click();
              }
          }
      }
  }
  

  Works perfectly with: for(ac=0;ac<allClearInputs.length;ac=ac+1){
  Fails miserably with: for(var ac in allClearInputs)