execute_async_script

The command to execute async javascript into the browser.

Similar to the execute_script command, you can pass in any javascript string and *args. The main difference is that you can execute asynchronous javascript. For example, using callbacks.

script = "var callback = arguments[arguments.length - 1]; " \
         "window.setTimeout(function(){ callback('timeout') }, 3000);"
driver.execute_async_script(script)

Syntax

py.execute_async_script(javascript: str) -> Any
py.execute_async_script(javascript: str, *args) -> Any

Usage

correct usage

# Yields the value of document.title
py.execute_async_script("return document.title;")

---or---

# Yields the .innerText of the element with the id of 'foo'
py.execute_async_script("return document.getElementById(arguments[0]).innerText", "foo")

incorrect usage

# Errors, 'execute_script' yields a WebElement, not a Pylenium Element
py.execute_async_script("return document.getElementById(arguments[0])").get()

Arguments

• javascript (str) - The async javascript to execute

• *args (Any) - A comma-separated list of arguments to pass into the javascript string

You can access the *args in the javascript by using arguments[0], arguments[1], etc.

Yields

• Any - This will return whatever is in the return statement of your javascript.

If you do not include a return, then .execute_async_script() will return None

Examples

# You can pass in complex objects
ul_element = py.get("ul")
py.execute_script("return arguments[0].children;", ul_element.webelement)
# We use the .webelement property to send Selenium's WebElement
# that is understood by the browser

# You can create complex javascript strings
get_siblings_script = '''
    elem = document.getElementById(arguments[0]);
    var siblings = [];
    var sibling = elem.parentNode.firstChild;

    while (sibling) {
        if (sibling.nodeType === 1 && sibling !== elem) {
            siblings.push(sibling);
        }
        sibling = sibling.nextSibling
    }
    return siblings;
    '''
siblings = self.py.execute_async_script(get_siblings_script, "foo")