[JS] Updating Object Property

Hey I'm kinda stuck,

I have an array tab objects with the properties .url and .title, what I'm trying to do is to update the properties of each object after a link has been pressed. The tabs .url property controls the URL that is loaded into an iframe and the title is the text on the tab.

function tabObject(url, title) {
       this.url = url;
       this.title = title;
}

function tabChange() {
       var url = "http://www.yahoo.com";
       tab[n].url = url;                           // n is the array element
       $('#tabs').attr('src', url);               //#tabs is the iframe ID
}

<a href="#" onclick="tabChange()">link</a>

For some reason this isn't updating the iframe.