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A First JavaScript Program
Later in this chapter, you’ll see how to create your own program in JavaScript, but in the interest of
getting you thinking about code right away, here’s a small webpage with an embedded JavaScript
program:
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document.write("Start Here!");
You’ll see later how to create a page like the one shown here. When viewed in a browser, the page
looks like Figure 1-1. I’ll show you how to create such a page later in the chapter.
FIGURE 1-1 A basic JavaScript program to display content.
The bulk of the code shown in the preceding listing is standard HTML (HyperText Markup Language)
and will be explained later. For now, you can safely ignore the code on the page except for the
three lines beginning with .
The opening and closing script tags tell the web browser that the upcoming text is in the form of
a script—in this case, it is of the type text/javascript. The browser sees that opening script tag and
hands off processing to its internal JavaScript interpreter, which then executes the JavaScript. In this
case, the entire code is merely contained on a single line: a call to the write method of the document
object, which then places some HTML into the document.
The actual JavaScript comprises a single line:
2 Start here! Learn JavaScript