jScript new tab

Im making a similar service to AddThis but im having one problem..

The whole script and posting to the selected sites works fine and it loads really nice in a jquery popup however when clicking for example on twitter it just goes to twitter, I would like it so it opens in a new tab the code im using is:

Code:

$(document).ready(function(){
$("a[sharewith]").click(function(ev){
var rel = $(this).attr("sharewith");
var url = encodeURIComponent(self.location.href);
var title = encodeURIComponent($("title:first").html());
rel = rel.replace("{url}",url);
rel = rel.replace("{title}",title);
self.location.href = rel;
return false;
});
});

and thats gets the url + title and shares it with sharewith="link here" and works fine, however how do i get it to open in a new tab?

ive tried target="_blank" on the html, jQuery – Open External Links In New Window/Tab | blogt0sk1, Open external links in a new tab/window using jQuery

ive also tried other stuff such as:

Code:

var rel = $(this).attr({ target: "_blank" });

anybody know any other possible ways?