void start run 2 times

I have this code at my void start, but why it run 2 times at the debug log, ita happen not only at start but at my UI button too. can some1 explain this

Code (CSharp):

1. void Start () {
2.         Debug.Log ("start");
3.     }

 

Log the name of the object. You probably have another object with the script on it

 

ooh like that, I have empty gameobject where the script I use. And at the same time I load that script in my UI button. How I make it just 1 script at all, I'm newbie at Unity

 

Just don't use the script on more than one object.

 

ok, I'll try and thanks for the explanation