## Example: Highlight By Age

Highlight Table by Age

    function highlightByAge() {
        let tableid = 'senatetable';
        let older = 70;
        let younger = 50;
        let mytable = document.getElementById(tableid);
        console.log("mytable is:");
        console.log(mytable);
        // get tbody (i.e. we dont' want to stripe the thead)
        let mytbody = mytable.getElementsByTagName('tbody');
        console.log("mytbody is:");
        console.log(mytbody);
        /*   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
        */
        let myrows =  mytbody[0].getElementsByTagName('tr');
        console.log("myrows is:");
        console.log(myrows);
        console.log("myrows length is: " + myrows.length);

        /*  Iterate over the node list of "tr" returned, setting
            the class appropriately
          */
        for(var i=0; i<myrows.length; i++) {
          let bdaystr = myrows[i].getElementsByTagName('td')[3].firstChild.nodeValue;
          console.log("bdaystr is " + bdaystr);
          let [month, day, year] = bdaystr.split('/');
          console.log(month + " " + day + " " + year);
          let bday = new Date(year, month, day);
          console.log("bday as Date object:");
          console.log(bday)
          let now = Date.now();
          console.log("now is " + now);
          let age = (now - bday)/(1000 * 365.25 * 24 * 60 * 60);
          age = Math.round(age);
          console.log(age);
          if (age >= older) {
            myrows[i].setAttribute('class','older');
          } else if (age <= younger) {
            myrows[i].setAttribute('class','younger');
          }
        }
      }