How to different hold and one click left button mouse?

Hi, here you go, it's working (at least the JS, is just translated for the C#, i dind't tested it). You can adjust what you call a "long click" by changing the 0.4 value to whatever you want :)

JS:

 private var t0:float;
 private var longClick:boolean;
 private var shortClick:boolean;
 
 /* INITIALIZATION */
 function Start () {
     t0 = 0;
     longClick = false;
     shortClick = false;
 }
 
 /* READ AT EACH FRAME */
 function Update () {
     if (Input.GetMouseButtonDown(0)){
            t0 = Time.time ;
     }
  
      if (Input.GetMouseButtonUp(0) && (Time.time - t0) > 0.4){
         longClick = true;
     }else if (Input.GetMouseButtonUp(0) && (Time.time - t0) < 0.4){
         shortClick = true;
     }
     
     // Don't forget to reset to false shortClick or longClick as soon as you use it
     // Unless what it will be still true at the next frame and cause issues
 }shortClick = false;
 }

C#:

 float t0;
 bool longClick;
 bool shortClick;
 
 /* INITIALIZATION */
 void Start () {
     t0 = 0f;
     longClick = false;
     shortClick = false;
 }
 
 /* READ AT EACH FRAME */
 void Update () {
     if (Input.GetMouseButtonDown(0))
         t0 = Time.time ;
  
      if (Input.GetMouseButtonUp(0) && (Time.time - t0) > 0.4f){
         longClick = true;
     }else if (Input.GetMouseButtonUp(0) && (Time.time - t0) < 0.4f){
         shortClick = true;
     }
     
     // Don't forget to reset to false shortClick or longClick as soon as you use it
     // Unless what it will be still true at the next frame and cause issues
 }