报错Invalid argument supplied for foreach()，什么原因？

$data[0] = array(
            "file"=>"jquery",
            "file"=>"bootstrap"
        );
    foreach($data as $val){
        $link = $val['file'].'.js';
    }
    foreach($link as $val){
        $links = "<script src=\'".$val['file']."\'></script>";
    }
    print_r($links);

输出：

Warning: Invalid argument supplied for foreach() in F:xampphtdocsxamppcmsAjaxindex3.php on line 10
Notice: Undefined variable: links in F:xampphtdocsxamppcmsAjaxindex3.php on line 13