JavaScript

Warnings

JavaScript is case sensitive. Everything in JavaScript is case sensitive. So you will have to be careful about upper- and lowercase characters in all statements, variable names, properties, methods, etc. For an example, the statement:

Document.write("Hello World")

results in the error message "Document object does not exist." The only problem here is the uppercase D. Therefore, the statement:

document.write("Hello World")

is correct.

<IMG> tags in same document can cause total weirdness. Many people have reported that if a page contains pictures (i.e. <IMG SRC> tags), and JavaScript code, the code behaves very strangely. The (peculiar) fix is to make sure that every <IMG SRC> tag contains a HEIGHT and WIDTH attribute.

JavaScript changes. Like everything else on the Internet, JavaScript is always evolving and changing. Therefore, the Internet itself is your best resource for current information. Though it's a bit advanced, one of the best online JavaScript references available is the one that comes right from the source, Netscape. You can use their online version, or download athe documents to your computer from Netscape Communications' JavaScript Library.