Here are the JavaScript source codes for the given problems: COMPARISON <script> var x = 50; var y = 68; var z = (x < y); alert(z); </script> LOGICAL <script> var x = 50; var y = 68; var z = (x == y && y == x); alert(z); </script> CONDITIONAL <script> var answer = prompt("What is the first calculating device? Abacus or Comptometer?", ""); var result = (answer == "Abacus") ? "Congratulation!" : "Try Again"; alert(