Exporting HTML tables to Excel (.xls) in a separate sheet

Content-type = application/vnd.ms-excel
Content-disposition = attachment;filename=whateverIsAppropriate.xls

$scope.items = [{
    name: "John Smith",
    email: "j.smith@example.com",
    dob: "1985-10-10"
}, {
    name: "Jane Smith",
    email: "jane.smith@example.com",
    dob: "1988-12-22"
},
...

# Find the all-NA rows, split the data, and get rid of the all-NA rows
breaks = rowSums(is.na(d)) == ncol(d)
dlist = split(d, f = data.table::rleid(breaks))
dlist = Filter(function(x) !all(is.na(x)), dlist)

# clean the remaining data
dlist = lapply(dlist, function(x) {
  nm = sapply(x[1:2, -1], paste, collapse = "_")
  x = x[-(1:2),]
  names(x) = c("whatever", nm)
  x
})
dlist
# $`1`
#     whatever header2_header2a header3_header3a header4_header4a
# 3     header           Number           Number           Number
# 4 attribute1           Number           Number           Number
# 5 attribute2           Number           Number           Number
# 6 attribute3           Number           Number           Number
# 
# $`3`
#       whatever header2b_header2bb header3b_header3bb header4b_header4bb
# 11      header             Number             Number             Number
# 12 attribute1b             Number             Number             Number
# 13 attribute2b             Number             Number             Number
# 14 attribute3b             Number             Number             Number

d = read.table(text = 'col1         col2       col3       col4
NA           header2    header3    header4
NA           header2a   header3a   header4a
header       Number     Number     Number
attribute1   Number     Number     Number
attribute2   Number     Number     Number
attribute3   Number     Number     Number
NA           NA         NA         NA
NA           NA         NA         NA
NA           header2b    header3b    header4b
NA           header2bb   header3bb   header4bb
header       Number     Number     Number
attribute1b   Number     Number     Number
attribute2b   Number     Number     Number
attribute3b   Number     Number     Number
NA           NA         NA         NA
NA           NA         NA         NA', header = T)