Selenium Webdriver 中的 executeScript 使用方法

1.使用executeScript 返回一个WebElement .

  下例中我们将一个浏览器中的JavaScript 对象返回到客户端（C#,JAVA,Python等）。

IWebElement element = (IWebElement) ((IJavaScriptExecutor)driver).ExecuteScript("return $('.cheese')[0]");

2.使用executeScript 和参数组合返回一个WebElement列表。

  下例中我们将客户端中的一个 IList<IWebElement> 对象传递到 浏览器中作为一个 JaveScript 对象使用。

IList<IWebElement> labels = driver.FindElements(By.TagName("label"));
IList<IWebElement> inputs = (IList<IWebElement>) ((IJavaScriptExecutor)driver).ExecuteScript(
    "var labels = arguments[0], inputs = []; for (var i=0; i < labels.length; i++){" +
    "inputs.push(document.getElementById(labels[i].getAttribute('for'))); } return inputs;", labels);

函数详细解释：

//
// Summary:
// Executes JavaScript in the context of the currently selected frame or window.
//
// Parameters:
// script:
// The JavaScript code to execute.
//
// args:
// The arguments to the script.
//
// Returns:
// The value returned by the script.
//
// Remarks:
// The OpenQA.Selenium.IJavaScriptExecutor.ExecuteScript(System.String,System.Object[])method
// executes JavaScript in the context of the currently selected frame or window.
// This means that "document" will refer to the current document. If the script
// has a return value, then the following steps will be taken:
// For an HTML element, this method returns a OpenQA.Selenium.IWebElement For a
// number, a System.Int64 is returned For a boolean, a System.Boolean is returned
// For all other cases a System.String is returned. For an array,we check the first
// element, and attempt to return a System.Collections.Generic.List`1 of that type,
// following the rules above. Nested lists are not supported. If the value is null
// or there is no return value, null is returned.
// Arguments must be a number (which will be converted to a System.Int64), a System.Boolean,
// a System.String or a OpenQA.Selenium.IWebElement. 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"

object ExecuteScript(string script, params object[] args);

翻译一下 ：

1.作用域：当前frame 或 window ,如果是在frame下执行，应该受到frame 的范围影响。

2.返回值：我们客户端以C#为例

JavaScript	c#
HTML element	OpenQA.Selenium.IWebElement
number	System.Int64
boolean	System.Boolean
其它类型	System.String
array	检查第一个元素，尝试转换为System.Collections.Generic.List`1
null	null
没有返回	null
Nested lists	不支持

3.参数：

C#	JavaScript
OpenQA.Selenium.IWebElement	HTML element
System.Int64	number
System.Boolean	boolean
System.String	string
其它类型	thrown exception

其他