WebDriver executeAsyncScript 与 executeScript [英] WebDriver executeAsyncScript vs executeScript

问题描述

executeAsyncScript 和 executeScript 有什么区别?我如何使用诸如 window.onload 之类的事件?我试过这样的事情

What is the difference between executeAsyncScript and executeScript? How can i use event such as window.onload? I tried something like this

((JavascriptExecutor) driver).executeAsyncScript("window.onload = function() {alert('Hello')}"); 

但是当然没用...所以如果有人知道它是如何工作的，请写一个例子

But of course it did not work... So if anyone knows how it works please write an example

推荐答案

(保持简单，正确.)

execteScript 和 executeAsyncScript 的相关区别是:

The relevant difference between execteScript and executeAsyncScript is this:

使用 executeAsyncScript 调用的函数将完成回调"作为最后一个参数，必须调用该参数以表示脚本已完成执行.

The function invoked with executeAsyncScript takes a 'done callback' as the last argument, which must be called to signal that the script is done executing.

这允许它与仅在使用回调时完成"的代码一起使用 - 例如.setTimeout 或异步 XHR.如果在超时限制内未调用完成回调"，则返回的承诺将被拒绝.

This allows it to be used with code that only 'finishes' when a callback is used - eg. setTimeout or asynchronous XHR. If the 'done callback' is not called within the timeout limits the returned promise will be rejected.

根据 webdriver.WebDriver.executeAsyncScript文档:

与使用 #executeScript 执行同步 JavaScript 不同，使用 [#executeAsyncScript] 执行的脚本必须通过调用提供的回调显式表示它们已完成.此回调将始终作为最后一个参数注入到执行的函数中..

Unlike executing synchronous JavaScript with #executeScript, scripts executed with [#executeAsyncScript] must explicitly signal they are finished by invoking the provided callback. This callback will always be injected into the executed function as the last argument..

也就是说，两个函数都会阻止 WebDriver 控制流，直到它们完成 - 要么在 executeScript 的代码末尾运行，要么在使用 executeAsyncScript 调用完成回调":名称中的async"表示所使用的信号机制，并不意味着/暗示 JavaScript 代码实际上是相对于 WebDriver 异步执行的.

That is, both functions block the WebDriver control flow until they complete - either running off the end of the code for executeScript or when calling the 'done callback' with executeAsyncScript: "async" in the name signifies the signal mechanism used and does not mean/imply that the JavaScript code is actually executed asynchronously with respect to the WebDriver.

这篇关于WebDriver executeAsyncScript 与 executeScript的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！