How to call case within switch case using javascript?

Just wrap the operations in functions so they are reusable

switch (something) {
case 1:
    operation1();
    break;
case 2:
    operation2();
    break;
case 3:
    operation3()
    operation1(); //call operation 1
    break;
default:
    defaultOperation();
    break;
}

You could do it like so:

switch(something){
  case 2:
         break;
  case 3:
         //do something and fall through
  case 1:
         //do something else
         break;
  default:
         break;
}

normally all code below a matched case will be executed. So if you omit the break; statement, you will automatically fall through to the next case and execute the code inside.

  switch(something){
      case 3:
      case 1:
             break;
      case 2:
             break;

      default:
             break;
    }

this should do the trick

combine the two cases:

switch(something){
   case 1:
   case 3:
          break;
   case 2:
          break;
   default:
          break;
 } 

var i = 3;

switch (i)
{
    case(3):
    alert("This is the case for three");

    case(1):
    alert("The case has dropped through");
    break;
    case(2):
    alert("This hasn't though");
    break;
}  

Not really a good idea though, leads to unreadable code