ciao a tutti, vorrei poter evidenziare una colonna onmouseover.
dato il codice in basso ci riesco solo se la colonna non ha un colspan altrimenti non si evidenzia l'intera colonna con i due <td> relativi ma solo la prima cella: il primo <td></td>.

come mai? dove sbaglio?

codice:
<STYLE>
  TABLE {border: 1pt lightgrey solid}
  TH {background: lightgrey; color: darkred; 
      border: 2px lightgrey outset; 
      cursor: default}
  TD {border-right: 2px lightgrey solid}
  .cover {background: navy; color: yellow}
  .rover {background: black; color: white}
</STYLE>

<script>
<!--

  var rowHighlight = true // turn on row highlights
  var colHighlight = true // turn off row highlights

  function getElement(el) {
    var tagList = new Object
    for (var i = 1; i < arguments.length; i++)
      tagList[arguments[i]] = true
    while ((el!=null) && (tagList[el.tagName]==null))
      el = el.parentElement
    return el
  }

  function checkHighlight(which) {
    var el = getElement(event.srcElement,"TH","TD")
    if (el==null) return
    if ((el.tagName=="TH") && (colHighlight)) {
      var idx = el.cellIndex
      var table = getElement(el, "TABLE")
      var column = table.all.tags("COL")[idx]
      if (which)
        column.className="cover"
      else
        column.className=""
    }      
    if ((el.tagName=="TD") && (rowHighlight)) {
      var row = getElement(el, "TR") 
      var table = getElement(row, "TABLE")
      if (which) 
        row.className = "rover"
      else
        row.className = ""
      cache = row
    }
  }



// -->
</script>
</head>

<body>
<TABLE ONSELECTSTART="return false" 
       ONMOUSEOVER="checkHighlight(true)" 
       ONMOUSEOUT="checkHighlight(false)" 
       CELLSPACING=0>
<COL WIDTH=100><COL WIDTH=100><COL WIDTH=100>
<THEAD>
  <TR>
    <TH>Column 1</TH>
    <TH>Column 2</TH>
    <TH colspan="2">Column 3</TH>
  </TR>
</THEAD>
<TBODY>
  <TR>
    <TD>Item 1</TD>
    <TD>Item 2</TD>
    <TD>Item 3</TD>
    <TD>kkk</TD>
  </TR>
  <TR>
    <TD>Item 1</TD>
    <TD>Item 2</TD>
    <TD>Item 3</TD>
    <TD>ll</TD>
  </TR>
  <TR>
    <TD>Item 1</TD>
    <TD>Item 2</TD>
    <TD>Item 3</TD>
    <TD>DDD</TD>
  </TR>
</TBODY>
</TABLE>
</body>