Email content using javascript (Close window)

I'm using the below javascript to send an email from storyline. It works as expected,  but a new tab/window opens when the javascript runs.  How do I eliminate the new browser window from opening but still execute the javascript? All of our learners will use Outlook.

var player = GetPlayer();

var email=player.GetVar("useremail");

var subject="Voicemail Script";

var body_start=new Array();

body_start[1]=player.GetVar("Greet1");

body_start[2]=player.GetVar("CRF");

body_start[3]=player.GetVar("CRQ");

body_start[4]=player.GetVar("Closing");

var mailto_link='mailto:'+email+'?subject='+subject+'&body='+body_start.join(" ");
win=window.open(mailto_link,'emailWin');