Sample (and verbose) boilerplate for accessing SharePoint list data

baselineSPListRequest.js

/**
 * Note: This example is _purposefully verbose_, for ease of reading.
 * 
 * In an ideal world, your generic function would return the list items, and
 * another function would actually be enqueued in the SOD call that calls
 * (in IE9) just Array.forEach() through them for one-by-one processing,
 * for example. Hope this helps!
 */

// This function will console.log items from the list you specify in the
// variable "list"
function doSomethingWithListItems() {
	// Your list goes here by name
	var list = 'Announcements';

	// The root path to the current site is...
	var webRoot = _spPageContextInfo.webServerRelativeUrl;

	// This gets the odata endpoint for the current site and the list you need
	var listSvc = webRoot + '_vti_bin/listdata.svc/' + list;

	// Who needs jQuery? This works in IE8+
	var request = new XMLHttpRequest();

	// Prepare to make the request
	request.open('GET', listSvc, true);

	// This is how we do it... when the XMLHttpRequest tells us something can be done
	request.onreadystatechange = function() {
		// Are we there yet?
		if (this.readyState === 4) {
			// Did we get there OK?
			if (this.status >= 200 && this.status < 400) {
				// Holla! We have data
				var responseData = JSON.parse(this.responseText);
				// Just the list items, please...
				var listItems = responseData.d.results; 
				// Do stuff with the listItems here
				for (var idx = 0; idx < listItems.length; idx++) {
					// Ideally something more than logging them to the console
					console.log(listItems[idx]);
				}
			} else {
				// Woe upon your code, something is amiss
				console.log('Error getting', list, '-', this.status, this.statusText);
			}
		}
	};

	// Let's actually do it; send the XMLHttpRequest!
	request.send();
}

// Okay, let's be absolutely sure that "secret" global _spPageContextInfo is
// available for us to use before we make our request, and that other
// SP initialization stuff is done that might interfere with our function
ExecuteOrDelayUntilScriptLoaded(doSomethingWithListItems, "init.js");