Monday, December 14, 2009

IE macro - how to get programmatic control over HTML elements - Tutorial(3)

Finding elements inside HTML frames/iframes hierarchy with Twebst Web Automation Library

Once you have started a web macro and you've got a Browser object to play with, it's time to get programmatic access HTML controls inside the web page. As any web developer should know, you can easily find elements inside a document using document.getElementById.

In the world of web automation things are a bit different; web macros need to access HTML elements in any web document and at any level of DOM hierarchy. The target HTML element can be inside frames/iframes loaded from various domains, subject of cross-frame scripting security restrictions (see my older posts: "When IHTMLWindow2::get_document returns E_ACCESSDENIED" and "When IHTMLWindow2.document throws UnauthorizedAccessException").

Here's a simple VBscript web macro that automates a Google search in Internet Explorer:
Dim core
Dim browser
Set core = CreateObject("Twebst.Core")
Set browser = core.StartBrowser("")

Call browser.FindElement("input text", "name=q").InputText("codecentrix")
Call browser.FindElement("input submit", "name=btnG").Click()

What is so great about the code above is the way FindElement method works: first it waits for the browser to load the HTML document then it searches for the element thru all frame/iframe hierarchy.

Once an Element is found you can perform actions on it like: Click, RightClick, InputText, Check, Uncheck, Select, Highlight etc. What is even cooler than this, is that you don't have to write these statements by yourself. They will be automatically generated by Twebst Web Recorder which you can get for free:

Get Free Web Recorder for Internet Explorer



Unknown said...

Hi Adrian,

(1) Does this web automation framework support web page written in Java and Java applet?
(2) If we use this framework from Python or VC++7, how should we install it?



Unknown said...

Hi Tian,

1). The framework does not support Java applets. HTML web pages that are generated by server Java code (like jsp) are of course supported.

2). Just download the setup and install it. The kit contains C#, VB.Net, C++, VBScript and JScript samples.

I don't know Python but I'm sure there is a way to use COM objects from Python as well.