Slider revolution 6.5.7 button callback

I have a custom css for a text layer:

.testColor{
	color:blue;
}

and I want to invoke that css class from the callback of a button using jQuery:

jQuery("#btn1").click(function(){
  	jQuery("#text1").addClass("testColor");
})

or to set the color of the text, this way:

jQuery("#btn1").click(function(){
	jQuery("#text1").css("color", "blue");
})

But when I press the button, the text changes briefly from white to blue, and becomes white again.

What can I do to force the css styles on callback action from the button?