Attempting to Speed up my Web App using Flash, Javascript, JSP
I am currently working on a web application using Flash, Javascript and using a JSP (running on Apache Tomcat). I am trying to speed it up.
The application is embedded into another page using an <iframe>. Often we will embed the applicaiton many times into one page.
The page in the iframe is a JSP with some Javascript and a Flash SWF. The basic structure is:
<html>
<head>
<script src="script1.js"/>
...
<script src="script8.js"/>
</head>
<body>
<object>
<param ... />
<param ... />
<param ... />
<embed src="myFlash.swf" ...>
</embed>
</object>
</body>
</html>
After doing some informal testing I have found that for each application that is added to a page the page takes an additional four seconds to load. This is a linear increse in time which makes sence to me.
LoadingTime = (4 seconds)*NumberApplications + (3 seconds)
I think that these are the candidates 开发者_StackOverflow社区for slowness:
- Javascript
- Flash
- Server Side Processing
- Download Time
Javascript
I have used Firebug to profile the Javascript but no function is taking large percentage of the time and the overall time seems very small. Here are the approximate results:
- Function A takes up 25% of the time. Its time (including nested calls) is 1.5 seconds*. This seems almost neglegable.
- Function B, C, D, E Take up less than 10%
- There are many other functions that take up less than 2% of the total time
It looks like the JS is fast and not the cause of the app being slow.
* This time is for when there are 21 apps on the page and the total loading time is 85 seconds
Flash
I don't know how to profile the Flash code. I see a grey loading bar for some of the SWFs (some of them skip the grey scroll bar). I think that profiling this is my next step.
Download
Looking at the Net tab in Firebug it looks like there are a couple of things that are a bit slow on the download. Each JSP has about 8 javascript files associated with it. Downloading the first one is always a little bit slow (takes about a full second). I am not sure why this is. I am wondering if it is because there are not enough connections supported by my Tomcat server.
Other questions that come to mind are:
- It is making requests for the same 8 js files for each jsp would it be possible to put the js files on the main page so they are only requested once.
- Should I increse the number of connections to Tomcat?
- Since I am loading many applications I would like
app1to begin initializing itself after it has downloaded (and not wait forapp2to finish downloading). How can I see whenapp1has begun running, relitive to the downloads
Server Side Processing
I think that any Server side processing should be reflected by the download time. For example if one of the JSPs is taking a long time it would be easy to see since the JSP will take a long time to download.
Question
- What is the standard way to figure out what the slow part of the web app is?
- What is the easiest part to speed up?
- I know have some idea about how long some things are taking (download and JS) but I don't know how these two relate to each other. When does the JS start executing? When the download is finished or when it is finished for that file?
- Are there other things other that could be making my applicaiton slow?
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