Dynamic Documents Using JavaScript

Dynamic documents created using JavaScript provide all the functionality of static documents written in HTML. If you can write it in HTML, you can write it on-the-fly in a document script.

In fact, you can write your whole document in a script which converts document properties into a formatted area that can be placed at the beginning of any document you write. You can also have a script after the BODY tag that writes a document footer in a similar fashion.

You cannot change anything on your current page once the document is finished. If you want to write to the current document, you have to open it and write to it via scripts placed at the beginning and end of the document.

There is also another option to write to the current document.For this purpose, you can also choose to rewrite the entire document.

A document is open until you specifically close it or until the browser runs out of things to write about it. When you first open a window, the document associated with that window also opened.You can then write to it with a header script. Then the browser writes all of the body if there is one, and anything it finds in the footer script if there is one.

When it reaches the end of the HTML text, it automatically closes the document. Note that if you open a new window with myNewWin = self.open('', 'NewWin'), you do not have to issue a document.open(). Just start writing on the blank page.

If you use the onMouseOver event to write to the status bar, you find that if you, move your mouse too quickly, you miss the status write. It is because it rapidly replaced by the browser's response to the event.

When you exit, the status written will stay there until you encounter another link. If you want to use the content of your link in a function called from an onMouseOver handler, you can pass the function the keyword this.

To provide a canvas for yourself to write on, use the document.open() command. It is a good idea to precede this with a document.close() command as a safety precaution, in case there is already a document open.

You can open or reopen a document in the current window or any window for which you have a reference. Opening a document in that window clears anything that is already there. Once the document is open, you can write to it.

If you try to write to a document that is not open, nothing will happen. No error will occur the command will just fail.

You can write anything to a nascent document, including scripts. If you are creating a window from scratch, then you have to write everything.

In JavaScript, the links array canvassed to provide a list of links in a document. Links have only one property, the target.

The target is not the URL pointed to by the link; rather, it is the window into which that URL loaded. Any link is also a location object so that you can dissect the link in the same way you dissect a location object.

Links can have an onClick handler just as buttons do. However, when the onClick handler finishes, the URL specified by the link will be loaded. If you do not want the link to go anywhere, just specify the current URL as its destination.

And if you want to use a link to execute a function, use HREF= 'javascript: myfunc()'. Myfunc() can call a function or contain JavaScript code. For example, HREF='javascript: self.close()', immediately closes the current window.

Both text and images can be links. You can include both in the same link if you want so that clicking either the text or the image will activate the link's events.

Anchors consist of text or images in your document that is marked, usually named, and referenced by a link within the same document.

The document object has an anchors array, but at this time its use is quite limited.

You can find out how many anchors are on the page using the length property. The property arrays anchors[i].value or anchors[i].name can be accessed without error, but will also be empty.

Because images can be links, you can use them as buttons to call functions if you use javascript: xxx() as the HREF instead of a URL.

The location, title, lastModified, and referrer are the four properties that are very useful in keeping your documents up to date.

These resources are used to write a header or a footer for your documents dynamically.

The status window created with a javascript openStatus link attached to an image. This function,openStatus, creates a new window with everything turned off but the status bar. It sizes the window so that only the status bar is showing.

It also checks that the window created by examining aStatWin for a null value.It places a dummy button in aStatWin and sets the initial and default status.

The setStatus() function checks to see if aStatWin exists before it tries to address one of its objects. If aStatWin does exist, setStatus changes the content of its status bar. setStatus() then sets the focus on the dummy button in aStatWin to bring the window to the front.

It's done by a call to the setFocus() method. You can close it using an image button linked with a call to close(). The close() function simply closes aStatWin and makes sure that its value is reset to null.

You can place your form element values, or anything else, in the location's search property. As long as you precede it with a question mark (?), location.search will retrieve it.

However, not all non-alphanumeric characters can be placed in the string or recovered intact. If you are going to concoct a home-grown search string, you may either need to encode the parameters yourself or not allow non-alphanumeric characters.