Table striping with Javascript

• United States Senate Table - Plain
• United States Senate Table - Striped with JS

• Use onload event attribute of body element to call striping function.
• Will use Document Object Model to access parts of the page
• Basic flow:
  • Get the table to stripe (getElementById)
  • Get the table body (getElementsByTagName)
  • Get the rows within the table body (getElementsByTagName)
  • Go through each row, and assign an "evenRow" or "oddRow" class attribute
    (for loop and setAttribute DOM method)

function stripeTable(tableid) {
  var mytable = document.getElementById(tableid);
  // get tbody (i.e. we do not want to stripe the thead)
  var mytbody = mytable.getElementsByTagName('tbody');
  /*   getElementsByTagName gives us a Node List, so we need
     to access it as a list (Array), arrayname[i].
     Find all the tr within the tbody
  */                                          
  var myrows =  mytbody[0].getElementsByTagName('tr');
  /*  Iterate over the node list of "tr" returned, setting
      the class appropriately
    */  
  for(var i=0; i<myrows.length; i++) {
    if ((i + 1) % 2 == 0) {
      // even row -- the "%" operator is the "modulus" or remainder
      myrows[i].setAttribute('class','evenRow');
    } else {
      // odd row
      myrows[i].setAttribute('class','oddRow');
    }
  }
}