`XMLHttpRequest` and `fetch()` are two powerful functions in JavaScript that can be used to make Ajax calls. XMLHttpRequest (XHR) is a legacy technology that’s been around since the early days of the web. It allows you to make HTTP requests from the client side, and it’s still widely used today. The fetch() function, meanwhile, is a newer addition to JavaScript that’s slowly taking over as the preferred way to make Ajax calls. It uses Promises, so it’s easier to write and debug, and it also supports streaming and other modern features.
Both XMLHttpRequest and fetch() are great tools for making Ajax calls, but fetch() is generally considered the better option for most applications. So if you’re looking for a way to make Ajax calls in JavaScript, give fetch() a try. We think you’ll be pleasantly surprised by the results!
Make HTTP Request in JavaScript
Here is an example of using XMLHttpRequest to make a GET request to retrieve data from remote API:
1 2 3 4 5 6 7 8 9 10 11 12 | const xhr = new XMLHttpRequest(); xhr.responseType = 'json'; xhr.onreadystatechange = () => { if (xhr.readyState === XMLHttpRequest.DONE) { console.log(xhr.response); } } xhr.open('GET', 'https://api.example.com/'); xhr.setRequestHeader('Authorization', 'Bearer ' + API_KEY); xhr.send(); |
Here is an example of using fetch() to make a GET request to retrieve data from a remote API.
1 2 3 4 5 6 7 | fetch('https://api.example.com/', { headers: { 'Authorization': 'Bearer ' + API_KEY } }) .then(response => response.json()) .then(data => console.log(data)); |
Both examples assume that you have an API key stored in a variable called API_KEY.
You can also use fetch() to make other types of HTTP requests, such as POST, PUT, and DELETE, by passing an options object as the second argument. For example:
1 2 3 4 5 6 7 8 9 10 | fetch('/url', { method: 'POST', body: JSON.stringify({ name: 'John', age: 30, }), headers: { 'Content-Type': 'application/json', }, }); |
Note that `XMLHttpRequest` and `fetch()` are asynchronous, which means that the code will not block while the request is being made. Instead, the response will be processed in a callback function or with a promise.