AJAX

Javascript runs on the client (i.e. in the web browser) yet is static text that is downloaded as part of a web page. Because Javascript is executable code, web pages with Javascript enhancements can behave more like traditional software applications than simple static information pages. One of the more powerful Javascript directives can pull information from a website or service to change part of the current page - without reloading the whole page. This feature is often called AJAX (Asynchronous Javascript and XML).  Here's an example.

DOM

Sample code for traversing structure of elements that comprise a HTML page Document Object Model (DOM).  Here is an example.

// unlike simple variables, array are passed to functions by refernce
test = new Array;
test[0] = 0;  //  nest depth
test[1] = 1;  //  continue recusion

traverse(window.document, test);

function traverse(node) {
	var res;
	var text;

	text = 'nest: ' + test[0] +
	  '\nnode type: ' + node.nodeType +
	  '\nname: ' + node.nodeName;
	if (node.nodeType == 3) {
		text += '\n' + node.nodeValue.substring(0, 63);
		if (node.nodeValue.length > 64)
			text += ' ...';
		}
	res = window.confirm(text);
	if (!res)
		test[1] = 0;
	if (test[1] && node.childNodes != null) {
		test['0']++;
		for (var i=0; i < node.childNodes.length; i++) {
			if (test[1])
				traverse(node.childNodes.item(i));
			}
		test['0']--;
		}
	}