I came across this useful bit of javascript when I had some parameters and wanted to call the server and get some data from the db(preferably in a nice json object). All in one line, as if I was calling a local function without having to mess with callbacks. ajax and jQuery make this very simple.

Here’s what the code looks like:

var jsonLoader = function(url, params) {
	this.url = url;
	this.params = params;
	this.retrievedData = {};
	this.getRawData();
};
jsonLoader.prototype.getRawData = function() {
	var json = $.ajax({
	type: 'POST',
	contentType: "application/json; charset=utf-8",
	url: this.url,
	data: JSON.stringify(this.params),
	dataType: 'json',
	success: this.setRawData(this),
	async: false
	});
};
jsonLoader.prototype.setRawData = function(self) { return function(json) { self.retrievedData = json; }; };

And you’d call it like this:

  var params = new Object();
  params.var1 = "something";
  params.var2 = 22;

  var data = new jsonLoader("/WebService/MyMethod", params);

  data.retrievedData.d.{json object name returned by the server}

The method blocks until data is retrieved(async: false), so you can start using data right away.

Make sure you have jQuery and JSON libraries loaded.

Credit to the original jsonLoader sniplet author for the idea, shown here tweaked to accept parameters.