Expandable list not getting content holder value

Hi,
we are using sitefinity 4.2. we need to create a list with many retailers name. onclick it should show shop name.  It should open only one drop down at a time, rest all have to be closed. here is our html version. we used simple javascript to work.

epins.com.sg/retail-fashion.html

Our client asking same function in sitefinity version. exactly similar to HTML Version with onclick arrow down. when i use expandable list to create this function. value of content holder not loading inside javascript dopostback. can u please help me how to add value of content holder??

Thanks & Regards,
Venkatesh