Ajax For Dummies®

Chapter 4. Ajax in Depth

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Returning JavaScript from the server

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Returning JavaScript objects

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Connecting to Google Suggest yourself

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Creating a live search

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Performing server-side validation

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Handling head requests

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Handling multiple XMLHttp requests at the same time

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“Hey!” says the highly-paid master Ajax programmer, “what’s all this about? I’m just doing my normal Ajax programming here, and some darn security message keeps popping up.”

“The browser’s giving you a security warning,” the CEO says. “It says your application is trying to access another Web site.”

“Well, that’s very helpful news,” the highly-paid master Ajax programmer says, “I know that.”

“You shouldn’t try to connect to another Web domain like Google from your JavaScript — didn’t you read Chapter 4 in Ajax For Dummies?” you say calmly, emerging from the shadows.

“Huh?” asks the master Ajax programmer.

“It’s okay,” you say, sitting down and taking over, “I’ll show you how this should work — for a substantial fee.”

You know Ajax adds power to your Web applications, but as this example shows, unless you know the tricks, problems such as this one can drive your users away. This chapter explains how you can best implement powerful Ajax techniques, such as connecting to Google for instant searches, returning JavaScript from ...