Dialog with a Dialog

I hope this can help you!.

var myWindow = new Window ("dialog", "Fitting Table");
var myInputGroup = myWindow.add ("group");
myInputGroup.add ("statictext", undefined, "Number of Columns:");
var myText = myInputGroup.add ("edittext", undefined, "");
myText.characters = 20;
var myButtonGroup = myWindow.add ("group");
myButtonGroup.orientation = "column";
var OkButton = myButtonGroup.add ("button", undefined, "OK");
var backbutton = myButtonGroup.add ("button", undefined, "Cancel");
OkButton.onClick = function(){
        onCLick();
}
backbutton.onClick = function(){
    myWindow.close();
}
function onCLick(){
    var myDialog = new Window ("dialog", "Table");
    var myInputGroup1 = myDialog.add ("group");
        myInputGroup1.add ("statictext", undefined, "Column Width value:");
    var myText = myInputGroup1.add ("edittext", undefined, "");
        myText.characters = 20;
    var myButtonGroup = myDialog.add ("group");
        myButtonGroup.orientation = "column";
    var OkTable = myButtonGroup.add ("button", undefined, "OK");
    var backTable = myButtonGroup.add ("button", undefined, "Cancel");
    OkTable.onClick = function (){
        myDialog.close();
        myWindow.close();
    }
    backTable.onClick = function (){
        myDialog.close();
    }
    myDialog.show();
}
myWindow.show();