Packaged autocomplete in an array widget

[ii2team...@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 attachment is read in the order of:
esn assigned msg --> esn cleared --> duplication reapears

Thanks in advance.