Packaged autocomplete for array widget

[ideasandinno...@gmail.com]

I have a requirement to autofill ESN(electronic serial number) in an array widget for multiple entries. While filling ESN values from the 2nd row itself I need to check for already entered ESN on the previous rows. In the packaged autocomplete there is a function 'onSelect' I have done the check and is able to identify the duplication. But after alert(ESN already entered), I need to clear the duplicate entry. I wrote this on the onSelect script and after clearing, the duplication reappears on the ESN field again(because it is written in the onSelect script). And I am not able to find a way to explicitly write onChange() script for this requirement.
I have raised a question before about the jQuery autocomplete method inside the array widget, and got response. But I have already asked doubts on the same there.
Question : https://groups.google.com/a/runmyprocess.com/forum/?hl=en&fromgroups=#!topic/supportforum/EiL9T-DxmNU
With this post I have attached the images showing problem occurring while the duplication check is done inside the onSelect script. Please respond with a solution to write other functions like onChange(), manualFunctions() for the packaged autocomplete. Any other approach through the jQuery autocomplete is also welcome. need URGENT HELP!!

The attached file order is:
esn assigned msg --> esn cleared --> duplication reappears

Thanks in advance.