Else not tripping even when If condition fails

programming flash
1

This segment creates the MCs for a preloaded slideshow. I want it to skip the creation of the MC and loader at the current index in the loop if a variable at that index is false, and then decrement the index and slideshow_length variable by one.

Looking at the code now, I suspect I need to pass si to another variable at each trip through the loop, and decrement that instead. But that still doesn’t seem to explain why the else condition isn’t tripping. Does it?

function init_slideshow():Void {
	for (si = 1; si < parseInt(slideshow_length) + 1; si++) {
		//sets default of all play_slide vars to true if not already defined [works]
		if (_level0['play_slide' + si] == undefined) {
			_level0['play_slide' + si] = true;
			//create loader and mc at idx if play_slide at idx is true [works]
			if (_level0['play_slide' + si] == true) {
				this['slide_loader' + si] = new MovieClipLoader();
				this.createEmptyMovieClip('slide_mc' + si, this.getNextHighestDepth());
			}
			else {
				//else, decrement idx; decrement slideshow_length variable [doesn't work]
				//else statement never trips, even when if returns false
				si--;
				_level0.slideshow_length--;
			}
			curr_ld = this['slide_loader' + si];
			curr_mc = _level0['slide_mc' + si];
			//load image into corresponding loader at idx
			curr_ld.loadClip(slide_path + slide_name + si + slide_ext, curr_mc);
			//hide all slides initially
			curr_mc._alpha = 0;
			curr_mc._x = Stage.width;
			curr_mc._y = Stage.height;
		}
		//report loading of final image 
		if (si >= slideshow_length) {
			curr_ld.addListener(slide_loader_listener);
			slide_loader_listener.onLoadInit = function(target_mc:MovieClip) {
				trace("last image loaded: " + target_mc);
			};
		}
	}
}