What I miss?

1.php:

```
<button id = "testtext">Show</button>
<script src="jquery-3.1.1.min.js"></script>
<script src="js.js"></script>

```

js.js:

```
$("#testtext").bind("click", previewNewShortnameFunc);
function previewNewShortnameFunc() {
    var lalalatext = "lalala";
    var lalalaint = 100;
    console.log("sent: " + lalalatext + " and " + lalalaint);
    $.ajax ({
        url: "testprint4.php",
        type: "POST",
        data : {str: lalalatext, int: lalalaint},
        success: function(data) {
            window.open("testprint4.php");
        }
    });
}

```

testprint4.php

```
<?php
$str = $_POST['str'];
$int = $_POST['int'];
echo $str;
echo $int;
?>

```

I see blank page instead of lalala100. What am I doing wrong?