Re: JSP Loading Page... Please wait while my code doesn't work!

From:
Nino <nino9stars@yahoo.com>
Newsgroups:
comp.lang.java.programmer
Date:
30 May 2007 23:46:52 -0700
Message-ID:
<1180594012.354875.205510@a26g2000pre.googlegroups.com>

I have tried, and tried again to build a "Please wait..." loading page
in JSP. I have read all the posts I could find on the matter and
incorporated what seemed to be a set way to do this.

Here is the premise that just about every bit of information I
gathered suggested:
In the HEAD tag:
        <STYLE>
                #waitPage { position: absolute; }
                #loadPage { position: absolute; visibility: hidden; }
        </STYLE>

        <SCRIPT language="JavaScript">
                function initWait () {
                        if (document.layers) {
                                document.layers['waitPage'].visibility = 'hide';
                                document.layers['loadPage'].visibility = 'show';

                        } else if (document.all) {
                                document.all['waitPage'].style.visibility = 'hidden';
                                document.all['loadPage'].style.visibility = 'visible';

                        } else if (document.getElementById) {
                                document.getElementById('waitPage').style.visibility = 'hidden';
                                document.getElementById('loadPage').style.visibility = 'visible';
                        }
                }
        </SCRIPT>

In the body tag:
<BODY onload="initWait();">

Within the body...
<DIV id="waitPage">
     This is where the graphics, or Please wait... text would go
</DIV>

<DIV id="loadPage">
     This is where all the work goes (function calls, etc)
</DIV>

And that's it!!! Well, I tried this and it doesn't work. Is there
anything I'm missing? Does it matter what engine renders my JSPs
(Tomcat)? Does it matter what kind of work is being done? The type of
HTML that is built into the waiting DIV tag (for example, can I use
table tags?)?


JSPs are completely[1] evaluated by the server into an internal buffer
and then sent to the browser all at once. Even if it weren't, you'd
want to call out.flush (); after your waitPage div had been output but
before the loadPage div was sent.


I actually ran some more tests, and out.flush(); did nothing. It never
ended up sending anything out. I tried switching around the visibility
of the layers to no avail. Once the JSP starts doing work, the browser
just spins until it's done and then advances. No waiting screen, not
out.flush();, nothing. Any other ideas? Any reason why out.flush()
might not be working?

Nino

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