In which major browsers are Promise available?

Promise is a JavaScript object used to handle asynchronous operations. It helps solve the problem of callback hell and allows us to handle asynchronous code more conveniently. Promises have become a very important part of modern JavaScript development, but they are not supported in all browsers. This article will explore which major browsers Promise is available in.

First, let’s take a look at Promise support in mainstream browsers:

1. Google Chrome: Promise has been a built-in object since Chrome 32 version and can be used in all browsers that have the version or higher of Chrome browser.
2. Firefox Firefox: Promise is supported starting with Firefox version 29 and can be used in all Firefox browsers with that version or higher installed.
3. Apple Safari: Promise has been supported since Safari 7 and can be used in all Safari browsers with that version or higher installed.
4. Microsoft Edge: Promises are supported for the first time in Edge 12 and can be used in all Edge browsers with that version or later installed.
5. Microsoft IE (Internet Explorer): Promise has limited support in IE 11 and needs to be handled manually using the polyfill library. The Polyfill library is a JavaScript library that fills in functionality that is not supported by the browser.

When using Promise in IE 11, you can use some common polyfill libraries, such as ES6-Promise and Bluebird, to provide Promise compatibility support. By adding these libraries, we can use Promise's API methods and syntax in IE 11. It should be noted that polyfill libraries may increase the loading time and size of the application, so the needs and performance requirements of the application should be taken into consideration when selecting a suitable polyfill library.

In addition to mainstream browsers, Promise can also be used in some other browsers, but minimum version requirements need to be met. For example:

1. Opera: Promise is supported starting from Opera 19 version.
2. Android browser: Promise is supported starting from Android 4.4 version.
3. UC Browser: Promise is supported starting from UC 10 version.

Please note that for some older browsers, such as IE 10 and earlier, Promise may not be supported. In this case, we can consider using other asynchronous processing methods, such as callback functions or using third-party libraries to handle asynchronous operations.

To summarize, Promise support in mainstream browsers is as follows: Google Chrome (version 32 and higher), Firefox (version 29 and higher), Apple Safari (version 7 and higher), Microsoft Edge (version 12 and above). Although older versions of IE browsers have limited support for Promise, we can still use Promise functionality in these browsers by using the polyfill library. Therefore, in development, we can safely use Promise to handle asynchronous operations, but we should choose an appropriate polyfill library to provide compatibility support based on the browser version of the target audience.

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