Captions are only available if your webroutine has Options(*METADATA)
// Get list
var list01 = wr.list("LIST01");
// Get list header details
var list01Hdr = list01.headers();
var deptHdr = list01Hdr.col("DEPTMENT");
var deptHeadings = deptHdr.headings();
// Get list entries
var list01Entries = list01.entries();
var rowCount = list01Entries.rowCount();
list01Entries.each(function(entry) {
var rowNumber = entry.row();
var deptValue = entry.col("DEPTMENT");
});