java script collapsible

Hi - I wrote the following php code and now I want to add collapsible function to this.
I am not sure how to add it.

when I run the attached php program (ee.txt) the output will be something like this.

Customer Oriented
   Another Process
   process 1

    4th process
    3rd Process

     Control of Documents
     some process

but I want all this to be collapsible because the number of processes may be more...
so i want output like below
+Customer Oriented
when i click on + i want to see the list.

How can change the attached php to do that.
generally in html I use data-role="collapsible"
but here when i used i got errors.

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In simple way thinking you can write css class and add class when page is getting loaded and on click (+) sign you can toggle it.

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