Not able to attach Handler on Listboxes in case of OnChange event already fired on java script code

[Edited By Anas. Please in the next time , use the code editor() to post a formatted code so that the others can read your code and provide help].

I am developing Test Recorder/Playback tool in C# Language.Tool able to record and playback some application perfectly,but facing issues in case of source code also having onchange event.
We are attaching handler for recording the script,basically OnClick for Textbox, OnChange for Dropdown list, Right now I am facing issue with Dropdown list,
Source code of Dropdown List is: 

See the code in select tag also onchange event is here.
<select onblur="setCustDirtyFlag();" id="custType" ...