如何在JavaScript中使用python变量? [英] How do I use python variable in a javascript?

问题描述

我一直在寻找一种使用selenium的webdriver访问不可见文本字段的方法.我让它正常工作的唯一方法是使用

I've been on a prowl looking for a way to access a non visible text field using selenium's webdriver. The only way i got it to work is using

driver.execute_script("document.getElementById('text_field').value+='XYZ'")

但是，我不想使用 XYZ ，而是要使用python变量.

However, instead of using XYZ, I want to use python variables.

推荐答案

将变量传递给通过Selenium执行的JavaScript代码的正常方法是将变量传递给 execute_script :

The normal way to pass variables to the JavaScript code you execute through Selenium is to just pass the variables to execute_script:

foo = "something"
driver.execute_script("""
var foo = arguments[0];
document.getElementById('text_field').value += foo;
""", foo)

您可以通过在JavaScript端检索参数. arguments object .您可以执行此操作，因为传递给 execute_script 的代码被包装在一个函数中，因此执行的内容类似于:

You retrieve the argument on the JavaScript side through the arguments object. You can do this because the code you pass to execute_script is wrapped in a function so what is executed is something like:

function () {
    var foo = arguments[0];
    document.getElementById('text_field').value += foo;
}

，然后使用传递给 execute_script 的参数来调用该函数.这些参数由Selenium自动序列化.

and the function is called with the arguments that were passed to execute_script. The arguments are serialized automatically by Selenium.

使用 .format 进行插值或连接字符串是执行此操作的脆弱方法.例如，如果您执行'var foo ='+ foo +'"'，则只要您的 foo 变量中带有双引号(与'var foo ="{0}"'.format(foo)).使用 json.dumps 可以避免这种情况，并且在大多数情况下都可以使用，但是并不能解决以下问题:

Interpolating with .format or concatenating strings are fragile ways to do it. For instance if you do 'var foo = "' + foo + '"' this will break as soon as your foo variable has a double quote in it (same with 'var foo = "{0}"'.format(foo)). Using json.dumps is going to avoid this and will work in most cases but it does not take care of something like this:

el = driver.find_element(".something")

// Do stuff with el on the Python side.

driver.execute_script("""
var el = arguments[0];
// Do something with el on the JavaScript side.
""")

Selenium知道如何在找到JavaScript对象时将其转换为DOM对象时将其转换为Python对象. json.dumps 不会执行此操作.

Selenium knows how to convert the Python object it gives you when you find an object to a DOM object on the JavaScript side. json.dumps does not do this.

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