Add An Enter Button To a Preloader

Question

On my site I have 2 scenes and I'd like to add an 'Enter' button for moving from the preloader to the main site. How would I do that in this code?
stop();
preloader._width = 0;
preloader._visible = preloader_bg._visible = true;
preloader.onEnterFrame = function()
    filesize_total = _root.getBytesTotal();
    if( filesize_total == 0 ) filesize_total = 1;
    percent = Math.round( _root.getBytesLoaded() / filesize_total * 100 );
    txt = percent + "%";
    preloader._width = percent * 3;
    if( percent == 99 )
        delete this.onEnterFrame;}
enter_btn.onPress
     gotoAndPlay("flashmo_dream", "start");

Answer 1

I don't know where you are getting these tutorials, but they sound like they are very, very old. Along with not using AS2, you shouldn't be using scenes. Scenes are a left over method from the very earliest versions of Flash.
The objective in preloading content is that you are loading in new content before the user needs it. If you are doing this loading well, the user will not know that the operation went on. Any sort of loading screen should only be seen if the user calls for content that has not loaded yet. Your design objective should be to show something to the user as quickly as possible when the user hits your site. Load in your additional content and then let the user experience your site.
If you create a button on the stage in the same frame as your preloader object and name that button "enter_btn", then the code that you've shown above should do what you want.
I haven't used AS2 in many years. I don't remember a lot about its syntax, but from what I read of your code, it looks like you are measuring the loading of the file that contains the preloader object. This methodology can lead to a problem. When Flash begins working, a certain amount of the movie has to load before anything is seen on the screen. This means that the loading telltale that you have set up in your code will never show "0%", and probably not even "50%".
Here's a good tutorial that uses AS3 and fully explains the code and how the loader operates: http://flashexplained.com/preloaders/basic-loading-bar-preloader/
Here's another: http://www.republicofcode.com/tutorials/flash/as3preloader/
And here's a third: http://flashexplained.com/preloaders/making-the-complete-internal-preloader-in-flash-8-wit h-a-loading-bar-and-mathematical-preloaders/
Take a look at those examples and compare and contrast their methods.