It won't hurt...
It may make your web feel better...
Be careful! Don't gulp it!
After this lesson you will be able to:
The downside of Java is that to create your own applets, you must learn a pretty complex programming language or try to use some of the newer software tools that make the coding less difficult. The other downside is that many Java applets can take a disturbing amount of time to download and run, essentially stalling your web page until it "loads" (in our opinion, waiting to load a scrolling banner is not too many notches above the <blink> tag!).
Hopefully by now you have a sense that as a web browser reads in the HTML code for a page, it starts assembling and displaying the page layout from the top down, so that as a page may partially display even as the browser is reading in the later parts of the HTML document. As each HTML code is read in the browser reacts and formats, without asking any questions.
The command to make this happen looks like:
Now if we simply inserted this into our HTML file like:
The alert message would pop up immediately as the browser read the code, likely not what we want. To see this in action, try this test page.
Now we will throw some more programming jargon at you! Don't recoil in horror!
The big "parent" is the "navigator"- it has many different "properties" that describe more or less the web browser you are using, i.e. what kind (NetScape, Microsoft, etc) and version number. Below is the "window" object that describes the properties of one web window, with its own special properties. Next down is the "document" object, that describes information about a particular web page, say its URL, the time it was last changed, how many links there are in the page. And within the document object are many more objects that we will see soon.
Are you still with us? Do not worry about the forms and menus mentioned above, we will cover them in lesson 28.
Sometimes we can use this type of structure to "test" or get some value from our web page environment, known as properties. Other times, we use this structure to change these values or properties.
This is an introduction, so we have not made any changes to our project.
Review topics for this lesson:
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