switch Control Structure

Here is the code that generates different types of lists based on the user's choice. It uses the DOM rather than the outmoded write/ln()approach.  Note that we put the <script> block at the bottom of the XHTML markup so that the page has completely rendered before the code in the block executes.  This is required because the code looks for a markup element within the page which must already exist (i.e. be rendered) before it can be used.

var strChoice,             // user's choice
      strStartTag,           // starting list item tag
      strEndTag,             // ending list item tag
      boolValidInput = true, // flag that indicates if input is valid
      strListType;           // list type as a string

strChoice = window.prompt( "Select a list style:\n1 (bullet), 2 (numbered), 3 (lettered)", "1" );

switch ( strChoice ) {
   case "1":
     strStartTag = "<ul>";
     strEndTag = "</ul>";
     strListType = "<h1>Bullet List</h1>"
     break;
   case "2":
     strStartTag = "<ol>";
     strEndTag = "</ol>";
     strListType = "<h1>Ordered List: Numbered</h1>"
     break;
   case "3":
     strStartTag = "<ol type = 'A'>";
     strEndTag = "</ol>";
     strListType = "<h1>Ordered List: Lettered</h1>"
     break;
   default: // Other choices are invalid so set the flag for that
     boolValidInput = false;
}

if ( boolValidInput == true )
   {  var strDisplay = "<h2>Code Output:</h2";
      strDisplay += strListType + strStartTag;
      for ( var i = 1; i <= 3; ++i )
         strDisplay += "<li>List item " + i + "</li>";

      strDisplay += strEndTag;
   }
else
   strDisplay += "Invalid choice: " + strChoice;

document.getElementById("output").innerHTML = strDisplay;