selenium webdriver 执行javascript代码 executeScript方法和executeAsyncScript方法

java.lang.Object executeAsyncScript(java.lang.String script, java.lang.Object... args)

Execute an asynchronous piece of JavaScript in the context of the currently selected frame or window.

在当前选定的框架或窗口中的上下文中执行一个异步的JavaScript。

java.lang.Object executeScript(java.lang.String script, java.lang.Object... args)

Executes JavaScript in the context of the currently selected frame or window.

在当前选定的框架或窗口中的上下文中执行JavaScript。

executeScript
java.lang.Object executeScript(java.lang.String script,
                             java.lang.Object... args)
Executes JavaScript in the context of the currently selected frame or window. The script fragment provided will be executed as the body of an anonymous function.
Within the script, use document to refer to the current document. Note that local variables will not be available once the script has finished executing, though global variables will persist.


If the script has a return value (i.e. if the script contains a return statement), then the following steps will be taken:


For an HTML element, this method returns a WebElement
For a decimal, a Double is returned
For a non-decimal number, a Long is returned
For a boolean, a Boolean is returned
For all other cases, a String is returned.
For an array, return a List<Object> with each object following the rules above. We support nested lists.
Unless the value is null or there is no return value, in which null is returned
Arguments must be a number, a boolean, a String, WebElement, or a List of any combination of the above. An exception will be thrown if the arguments do not meet these criteria. The arguments will be made available to the JavaScript via the "arguments" magic variable, as if the function were called via "Function.apply"


Parameters:
script - The JavaScript to execute
args - The arguments to the script. May be empty
Returns:
One of Boolean, Long, String, List or WebElement. Or null.

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executeAsyncScript
java.lang.Object executeAsyncScript(java.lang.String script,
                                  java.lang.Object... args)
Execute an asynchronous piece of JavaScript in the context of the currently selected frame or window. Unlike executing synchronous JavaScript, scripts executed with this method must explicitly signal they are finished by invoking the provided callback. This callback is always injected into the executed function as the last argument.
The first argument passed to the callback function will be used as the script's result. This value will be handled as follows:


For an HTML element, this method returns a WebElement
For a number, a Long is returned
For a boolean, a Boolean is returned
For all other cases, a String is returned.
For an array, return a List<Object> with each object following the rules above. We support nested lists.
Unless the value is null or there is no return value, in which null is returned
Example #1: Performing a sleep in the browser under test.


   long start = System.currentTimeMillis();
   ((JavascriptExecutor) driver).executeAsyncScript(
       "window.setTimeout(arguments[arguments.length - 1], 500);");
   System.out.println(
       "Elapsed time: " + System.currentTimeMillis() - start);
 
Example #2: Synchronizing a test with an AJAX application:


   WebElement composeButton = driver.findElement(By.id("compose-button"));
   composeButton.click();
   ((JavascriptExecutor) driver).executeAsyncScript(
       "var callback = arguments[arguments.length - 1];" +
       "mailClient.getComposeWindowWidget().onload(callback);");
   driver.switchTo().frame("composeWidget");
   driver.findElement(By.id("to")).sendKeys("[email protected]");
 
Example #3: Injecting a XMLHttpRequest and waiting for the result:


   Object response = ((JavascriptExecutor) driver).executeAsyncScript(
       "var callback = arguments[arguments.length - 1];" +
       "var xhr = new XMLHttpRequest();" +
       "xhr.open('GET', '/resource/data.json', true);" +
       "xhr.onreadystatechange = function() {" +
       "  if (xhr.readyState == 4) {" +
       "    callback(xhr.responseText);" +
       "  }" +
       "}" +
       "xhr.send();");
   JSONObject json = new JSONObject((String) response);
   assertEquals("cheese", json.getString("food"));
 
Script arguments must be a number, a boolean, a String, WebElement, or a List of any combination of the above. An exception will be thrown if the arguments do not meet these criteria. The arguments will be made available to the JavaScript via the "arguments" variable.


Parameters:
script - The JavaScript to execute.
args - The arguments to the script. May be empty.
Returns:
One of Boolean, Long, String, List, WebElement, or null.