sliders instead of buttons

You can, but I think a dropdownlist would be better. on either of those, you just put an onChange function that will run the code you want.

var list = ['1. first','2. second','3. third'];

dlg = new Window('dialog','test');
dlg.dropLst = dlg.add('dropdownlist',undefined,list);

dlg.dropLst.onChange = function(){

    switch(parseInt(dlg.dropLst.selection)){
        case 0:
            //code here
            alert(dlg.dropLst.selection.text);
            break;
        case 1:
            //code here
            alert(dlg.dropLst.selection.text);
            break;
        case 2:
            //code here
            alert(dlg.dropLst.selection.text);
            break;        
        }    
    }
dlg.show();