Function Tells Error "object Required" As If The Select Id Was Not "type" Or The Checkbox Id Was Not "key"?

The javascript function addRowToTable() is called by a button, and replies a set of elements (select, input, checkbox) of the form.In this function, the creation of select calls another function CliK(sel.id)The problem is that this function tells me error "object required" as if the select Id was not "type" or the checkbox id was not "key"Where I go wrong?Posting the complete code

function addRowToTable()
{
var tbl = document.getElementById('tblSample');

[code]....