How do I get the TextBox Value since JavaScript? (Resolved)

Hey guys, i wanna get the TextBox Value since Js i tried it but no work:

var mystring= document.getElementById('MyIdTextBox').value;

and check with:

alert(mystring);

I specify in the construct2 the id as MyIdTextBox.

Please help

it's working for me...

"var mystring=document.getElementById('MyIdTextBox').value;alert(mystring);"[/code:2o1dfeav]

[img="https://media.giphy.com/media/3o6oziL9Zy9d7fVa7u/giphy.gif"]

ohh man soo cool, I can create external functions and then call with this, thank you.