Hi Eham,
Try this
Method 01
Goto Launch => Property name => Extension => Configure tracking code with custom code and paste the below code

var x = document.getElementsByTagName(button).getAttribute(csk-text);
evar1 = var x
Use the 1 as per the evar number availablity
Method 02
Goto Launch => Property name => Data element

Post this code in open editor: var x = document.getElementsByTagName(button).getAttribute(csk-text);
then Add Rule
Goto Launch => Property name => Rule

Hope this helps.
Regards,
Kumararaja K