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Jun 29th, 2005

Need to Preload many Images (and show a wait screen)

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I have a website at:
http://www.outingsunlimited.com
This site has quite a few "mouseover" images (37 actually) and I need to preload them before I start.
When someone goes to the site, while the images are loading.....the screen is just blank and they think there is a problem.....

HELP !!

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bitfiddler

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Jun 29th, 2005

Re: Need to Preload many Images (and show a wait screen)

I wrote a system to do this a few years ago. You can look at what I did by going to http://www.mvirony.com/, then navigate to the Boat Layout page. When you hit the home page, make sure you allow popups for the site. There aren't any ads or anything, but the Boat Layout page uses a popup window to tell the user to wait while images load--and you are especially interested in this part. Once images are loaded, the popup window closes automatically. (I coded this solution before popup ads were a big problem, and thus, before everybody had popup blockers.)

Simply view the source of the page to look at my javascript. Notice near the top of the script, I pop a window--this window loads a small page telling the user to please wait while images load. Then look at the LoadPhotos() function. This creates a javascript image variable for each of the large images--there are 3 which is why I loop 3 times. Notice I named my three images layout1.jpg, layout2.jpg, and layout3.jpg. Finally, notice that on window load (window.onload), I close the popup window.

I hope you are able to make sense of it to create your own solution. It works great, except if I were coding this today, I'd use a DIV that I dynamically display then hide once the images are loaded. Unfortunately, ad spammers have killed all legitimate use of popup windows.

Troy

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Posting Whiz

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Jun 30th, 2005

Re: Need to Preload many Images (and show a wait screen)

Quote originally posted by Troy ...

I wrote a system to do this a few years ago. You can look at what I did by going to http://www.mvirony.com/, then navigate to the Boat Layout page. When you hit the home page, make sure you allow popups for the site. There aren't any ads or anything, but the Boat Layout page uses a popup window to tell the user to wait while images load--and you are especially interested in this part. Once images are loaded, the popup window closes automatically. (I coded this solution before popup ads were a big problem, and thus, before everybody had popup blockers.)

Simply view the source of the page to look at my javascript. Notice near the top of the script, I pop a window--this window loads a small page telling the user to please wait while images load. Then look at the LoadPhotos() function. This creates a javascript image variable for each of the large images--there are 3 which is why I loop 3 times. Notice I named my three images layout1.jpg, layout2.jpg, and layout3.jpg. Finally, notice that on window load (window.onload), I close the popup window.

I hope you are able to make sense of it to create your own solution. It works great, except if I were coding this today, I'd use a DIV that I dynamically display then hide once the images are loaded. Unfortunately, ad spammers have killed all legitimate use of popup windows.

I'm fairly new to this "java" thing but I think I can get thru your code all right.
BTW, since it is "today"....how would you use the DIV ?
Did u look at the images I am loading at
http://www.outingsunlimited.com
????

bitfiddler

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Jun 30th, 2005

Re: Need to Preload many Images (and show a wait screen)

The "popup" works great...thx.....
but the "popup" won't close after the pics load ?????

Here is the code

<html>
<head>

<script language="javascript">
var winLeft = (screen.width-400)/2;
var winTop = (screen.height-150)/2;
var winWait = window.open("wait.htm","WinWait","width=400, height=150,top="+winTop+",left="+winLeft+",location=no, menubar=no, status=no, toolbar=no, scrollbars=no, resizable=no");
var iOff = new Image(); iOff.src = "indicatorBlank.gif";
var iOn = new Image(); iOn.src = "indicator.gif";
var photos = new Array(37);
LoadPhotos();

function SwapImg(x,imgSrc) {
document.getElementById(x).src = imgSrc;
}

function ShowPhoto(i) {
if (photos[i]) {
document.getElementById('iPhoto').src = photos[i].src;
}
}

function LoadPhotos() {
imgSrc = "images/TEXTPIC-659X367-1.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[1] = imgVar;
imgSrc = "images/TEXTPIC-659X367-4.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[2] = imgVar;
imgSrc = "images/TEXTPIC-659X367-5.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[3] = imgVar;
imgSrc = "images/TEXTPIC-659X367-6.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[4] = imgVar;
imgSrc = "images/TEXTPIC-659X367-7.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[5] = imgVar;
imgSrc = "images/TEXTPIC-659X367-8.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[6] = imgVar;
imgSrc = "images/TEXTPIC-659X367-9.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[7] = imgVar;
imgSrc = "images/TEXTPIC-659X367-10.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[8] = imgVar;
imgSrc = "images/TEXTPIC-659X367-12.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[9] = imgVar;
imgSrc = "images/TEXTPIC-659X367-13.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[10] = imgVar;
imgSrc = "images/TEXTPIC-659X367-16.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[11] = imgVar;
imgSrc = "images/TEXTPIC-659X367-17.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[12] = imgVar;
imgSrc = "images/TEXTPIC-659X367-18.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[13] = imgVar;
imgSrc = "images/TEXTPIC-659X367-20.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[14] = imgVar;
imgSrc = "images/TEXTPIC-659X367-AGENCIES.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[15] = imgVar;
imgSrc = "images/TEXTPIC-659X367-SITE-SEARCH1.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[16] = imgVar;
imgSrc = "images/TEXTPIC-659X367-STATE-SELECT.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[17] = imgVar;
imgSrc = "images/TEXTPIC-659X367-CONTACT-US.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[18] = imgVar;
imgSrc = "images/TEXTPIC-494x275-1.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[19] = imgVar;
imgSrc = "images/TEXTPIC-494x275-4.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[20] = imgVar;
imgSrc = "images/TEXTPIC-494x275-5.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[21] = imgVar;
imgSrc = "images/TEXTPIC-494x275-6.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[22] = imgVar;
imgSrc = "images/TEXTPIC-494x275-7.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[23] = imgVar;
imgSrc = "images/TEXTPIC-494x275-8.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[24] = imgVar;
imgSrc = "images/TEXTPIC-494x275-9.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[25] = imgVar;
imgSrc = "images/TEXTPIC-494x275-10.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[26] = imgVar;
imgSrc = "images/TEXTPIC-494x275-12.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[27] = imgVar;
imgSrc = "images/TEXTPIC-494x275-13.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[28] = imgVar;
imgSrc = "images/TEXTPIC-494x275-16.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[29] = imgVar;
imgSrc = "images/TEXTPIC-494x275-17.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[30] = imgVar;
imgSrc = "images/TEXTPIC-494x275-18.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[31] = imgVar;
imgSrc = "images/TEXTPIC-494x275-20.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[32] = imgVar;
imgSrc = "images/TEXTPIC-494x275-viewbystate.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[33] = imgVar;
imgSrc = "images/TEXTPIC-494x275-SITESEARCH1.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[34] = imgVar;
imgSrc = "images/TEXTPIC-494x275-STATESEL.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[35] = imgVar;
imgSrc = "images/TEXTPIC-494x275-CONTACTUS.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[36] = imgVar;
imgSrc = "images/TEXTPIC-659x367-view-by-state.jpg";
imgVar = new Image(); imgVar.src = imgSrc;
photos[37] = imgVar;

}

function LoadTrigger() {
winwait.close();
}

window.onload = LoadTrigger;

</script>

</head>

<body>

</body>
</html>

bitfiddler

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Jun 30th, 2005

Re: Need to Preload many Images (and show a wait screen)

First of all, because this is a pet-peeve of mine, it's "Javascript"--not "Java". The two are not even related. Javascript is not a scripting subset of Java. However, VBScript is a scripting subset of Visual Basic (VB).

Looking at your code, I don't see a problem, but are you sure there aren't any javascript errors? If you are using IE, when your page loads, do you notice a small error icon in lower left? If you use Firefox, it has an excellent Javascript Errors Console window that you can leave open to see any and all errors--it's a great tool for development.

You can create a DIV like this:

JavaScript / DHTML / AJAX Syntax (Toggle Plain Text)
<div id="waitdiv" style="position:absolute;top:100px;left:100px;padding:25px;font-size:20pt;">Please wait...images loading...</div>
<div id="waitdiv" style="position:absolute;top:100px;left:100px;padding:25px;font-size:20pt;">Please wait...images loading...</div>

Of course you can put any HTML you want inside the div and change the style to whatever you want. Then, in your LoadTrigger() function, do this:

JavaScript / DHTML / AJAX Syntax (Toggle Plain Text)
document.getElementById('waitdiv').style.display = 'none';
document.getElementById('waitdiv').style.display = 'none';

Troy

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Posting Whiz

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Jun 30th, 2005

Re: Need to Preload many Images (and show a wait screen)

Thx a million....the "popup" problem was that I had the wrong spelling for "winWait"...I had a lower-case "w".
Also, the <DIV> function works great !!

Thanks again.

bitfiddler

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