// these three methods are built in into 
// the JavaScript String object;
// they can be called on any string;


// there are three event handlers in the form
// that call a string method;
// the if (...) statement below checks the
// name of the field from where the call
// was made and associates the name with one method.

// we could have written three if (...) statements
// (without the else if (...) statements )
// since we have three unique conditions that
// are mapped to a single method,
// but in that case every function call would
// test all every if (...) statement in the 
// function; this way a function call moves
// through the if (...) else if (...) block
// until it finds a match and returns;


  function doStringFunction(myString, field)
  {
    if (field.name == "showStringLength")
    {
      field.value = myString.length;
    }
    else if (field.name == "showUpperCase")
    {
      field.value = myString.toUpperCase();
    }
    else if (field.name == "showLowerCase")
    {
      field.value = myString.toLowerCase();
    }
  }
  


// Note: for short assignment statements like these examples
// we didn't need to write a function at all; we could have
// made each assignment in the event handler statement;
// This is only an example without any claims on efficiency.
// However, it is a good idea to set up functions if calls are 
// made frequently, even if the action performed seems trivial.
// It saves coding and puts important pieces of code in places
// that are easy to find and maintain.