assigning index number to row in table-CodePudding

I want to add an index number to each row in a table automatically, like the one in the screenshot that I got from bootstrap's site here, I have tried multiple solutions but kept getting an index of -1 for all the rows, I would really appreciate the help, thank.

CodePudding user response：

Does this work for you?

// tbl is the table
var rows = tbl.rows; n = 1;
for (i=0; i<rows.length; i  ) {
  row = rows[i];
  f = row.firstElementChild;
  if (f) {
    el = document.createElement(f.tagName);
    el.innerHTML = (f.tagName == "TH") ? "#" : n;
    row.insertBefore(el, f);
    if (f.tagName != "TH") n  ;
  }
}