How to Make HTTP GET Requests in JavaScript?

Making HTTP GET Requests in JavaScript

When working with web applications, retrieving data from remote servers becomes necessary. In JavaScript, performing HTTP GET requests allows developers to fetch data from specified URLs. This article explores the best ways to perform such requests, particularly within Mac OS X Dashcode widgets.

Using XMLHttpRequest Object

Browsers and Dashcode provide the XMLHttpRequest object, which enables developers to make HTTP requests from JavaScript. Here's an example of a synchronous request using this object:

function httpGet(theUrl) {
  var xmlHttp = new XMLHttpRequest();
  xmlHttp.open("GET", theUrl, false); 
  xmlHttp.send(null);
  return xmlHttp.responseText;
}

Asynchronous Requests

While synchronous requests provide quick results, they block the execution of other code and can lead to performance issues. Asynchronous requests allow the code to continue executing while the request is being made. The response is handled within an event handler.

function httpGetAsync(theUrl, callback) {
  var xmlHttp = new XMLHttpRequest();
  xmlHttp.onreadystatechange = function() { 
    if (xmlHttp.readyState == 4 && xmlHttp.status == 200)
      callback(xmlHttp.responseText);
  }
  xmlHttp.open("GET", theUrl, true);
  xmlHttp.send(null);
}

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