Please Help me out with this simple Extension for Selection in Listbox

[#1]

Can any one please help me out in building and extension which basically puts selection in Listbox using Extension code

function selection () {
obj1 =doc.GetObject("LB15",function(){obj1.Data.SelectTexts("GA")});

alert("Selection RAN !");
}

i am able to make selections but when i execute this method within

Qva.AddExtension("FloorPlan", function ()

    {

//Code Run the below function in an event handler of button

selection();

}

I have managed to run this code on the event handler of a Button but the thing is its running in a continuous loop ie I am getting continuous sequence of Selection -> Alert Box -> selection in the field .

Please can any one help me out to figure out how to break the loop and run this code (selection() ) on qlikview on Button only once .

Will be really very greatfull !!!!