Modify innerHTML using Selenium

Try this:

WebElement element = ...
((JavascriptExecutor)driver).executeScript(
  "var ele=arguments[0]; ele.innerHTML = 'my new content';", element);

Selenium WebDriver does not have any direct methods to do so to change the DOM itself. However we can use JavascriptExecutor to use javascript to modify the DOM.

check this example to change the background color. You will get an idea to change the innerHTML as well.