Colour duplicate values in html output

Hello,

I am looking to colour duplicate values in an html file. 

I have written a folder comparison ps script which shows output as below:

Name Length Version

Name length and version are the column names

Now there are many duplicate entries under name column which I need to highlight using any one colour. I have sorted the output under name using alphabetical order.

I just need to highlight all duplicate values using a particular colour. 

Thanks in advance.