3D double Jump

Hello,

I know that there are a lot of similar questions, but none of them helped me. I created a 3DBuzz character. Trying to tweak it a little.

 public void Jump()
 {
     if (TP_Controller.CharacterController.isGrounded)
     {
         VerticalVelocity = JumpSpeed;
     }        
 }

I have tried with doublejump = true; false. I tried with timer, i tried with counting times "jump" was pressed. Nothing really works. Either i can fly off the ground and just keep on floating, or it doesn't jump at all. I think its really hard to put the definition for unity when and only when to double jump, as condition !isGrounded keeps on being true while in the air, thus i should give it another if or whatever condition to only press it once. But with no luck. If such code is not enough, i can paste it all.

EDIT!!!!!!!!!

Nevermind. My keyboard's space isn't working correctly, which meant, when i pushed it, it started to add lots of jumps.I switched to letter as last goto. It worked. So yeah... 4 hours lost due to keyboard :D facepalm

Code for others:

  public void Jump()
     {
         if (TP_Controller.CharacterController.isGrounded)
         {
             VerticalVelocity = JumpSpeed;
             jumptime = 0;
             canJumpz = true;
         }
         else
         {
             if (canJumpz = true && jumptime < 1)
             VerticalVelocity = JumpSpeed;
             canJumpz = false;
             jumptime++;
         }