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ptg16476052 476 LESSON 17: Introducing JavaScript happens to be valid JavaScript, and the Console automatically evaluates it and ...

ptg16476052 The JavaScript Language 477 17 Printed after JavaScript is run. Output ▼ The page includes a single line of Java ...

ptg16476052 478 LESSON 17: Introducing JavaScript The document object is a representation of the current page that is accessible ...

ptg16476052 The JavaScript Language 479 17 That’s the string representation of the document object. Many programming languages w ...

ptg16476052 480 LESSON 17: Introducing JavaScript This example uses the Math object, another object built in to JavaScript. It p ...

ptg16476052 The JavaScript Language 481 17 Let’s break down a variable declaration into pieces. Here’s a declaration: var messag ...

ptg16476052 482 LESSON 17: Introducing JavaScript do long void double native volatile else new while enum null with eval package ...

ptg16476052 The JavaScript Language 483 17 Let’s look at a simple example, which will work in the Console: var colo r = "red"; i ...

ptg16476052 484 LESSON 17: Introducing JavaScript You can also use the! operator, which reads as “not,” to negate any Boolean ex ...

ptg16476052 The JavaScript Language 485 17 while Loops The basic structure of a while loop looks like this : var color = 'blue'; ...

ptg16476052 486 LESSON 17: Introducing JavaScript Even though the test in the loop will not pass , it will still run once becaus ...

ptg16476052 The JavaScript Language 487 17 Functions can be writ ten to accept multiple arguments. Let’s look at another functio ...

ptg16476052 488 LESSON 17: Introducing JavaScript Output ▼ Functions are called using the function name, followed by parentheses ...

ptg16476052 The JavaScript Language 489 17 Boolean values represent a state of either true or false. You’ve already seen some ex ...

ptg16476052 490 LESSON 17: Introducing JavaScript Object properties are accessed through what’s known as dot notation. You can a ...

ptg16476052 Events 491 17 The JavaScript Environment I’ve taken you on a very brief tour of the JavaScript language, but beyond ...

ptg16476052 492 LESSON 17: Introducing JavaScript JavaScript code to events. The JavaScript environment monitors user activity a ...

ptg16476052 Events 493 17 Event Handler When It’s Called onfocus Whenever a visitor enters a specified form field onload Wheneve ...

ptg16476052 494 LESSON 17: Introducing JavaScript to an array of all the links in the document. It iterates over each of those l ...

ptg16476052 Workshop 495 17 At one time, using event-handler attributes to bind functions to events was the most com- mon approa ...