Screen displaying blank after adding button in browser

I am creating a simple banner add with a button covering the screen. I added the action Click to Go to Web Page to the button.. When I add the action the screen displays blank. When I remove the action the screen shows again but the button does not work. This is the action script that automatically adds when I double-click

Click to Go to Web Page

/* Click to Go to Web Page
Clicking on the specified symbol instance loads the URL in a new browser window.

Instructions:
1. Replace http://www.adobe.com with the desired URL address.
Keep the quotation marks ("").
*/

button_2.addEventListener(MouseEvent.CLICK, fl_ClickToGoToWebPage_4);

function fl_ClickToGoToWebPage_4(event:MouseEvent):void
{
navigateToURL(new URLRequest("https://www.ussoccer.com"), "_blank");
}

Please help. I'm very frustrated.