How to add Javascript from the Builder (runs 2 times or more)

[benjantonio]

Hello. What is the correct way to add "Javascript" to the Builder?

I tried this and other ways:

• I created a "Text Field" component.
  

• I placed a "Console.log" in "Custom Default".
  
  

• Finally, when I save my form, I open it and my console shows my console.log 2 times :(
  

Why did this happened? I've tried reading the documentation, but I'm having a bit of a hard time understanding it.
I hope someone can see this. I thank you very much!!