Handling Data for Ajax with JSON - Changing the JavaScript for JSON

Now let's look at the client JavaScript code. I've replaced two functions with one: I removed msPopulate() and nonMSPopulate() , and now all browsers use the populateJSON() function shown in Example 4-12.

Example 4-12. The populateJSON( ) function

function populateJSON() {
    var jsonData = req.responseText;

    var myJSONObject = eval('(' + jsonData + ')');

    var decimal = document.getElementById('decimal');  
  decimal.value=myJSONObject.conversion.decimal;

    var hexadecimal = document.getElementById('hexadecimal'); 
    hexadecimal.value= myJSONObject.conversion.hexadecimal;

    var octal = document.getElementById('octal'); 
   octal.value=myJSONObject.conversion.octal;

    var binary = document.getElementById('bin');
  binary.value=myJSONObject.conversion.binary;

    var hyper = document.getElementById('hyper');
  hyper.value=myJSONObject.conversion.hyper;
}

Summary

Remember that Ajax isn't a technology: it's a group of ideas that, used together, have proven very powerful. When you combine form manipulation with JavaScript, asynchronous callbacks withXMLHTTPRequest, and built-in XML with JSON parsers, you have something revolutionary--even though the individual pieces have been around for a while.

Combine these client-side technologies with Javas established server-side technologies, such as servlets, Struts, and JSF, and you've got a really powerful basis for building a new generation of interactive web applications.