ajax得到来自php echo的响应无法正常工作

I am trying to get response from php echo statement but I am not getting any response, my code seems fine but I don't know why it doesn't work

test.php
<?php echo "test" ?>

dashboard.php
<script type="text/javascript">
    function loadlink(){
        $.ajax({
            url: 'test.php',
            success: function (response) {
                alert("Hello"),
                document.getElementById("links").innerHTML=response;
            }
        });
    }

    loadlink(); // This will run on page load
    setInterval(function(){
        loadlink() // this will run after every 5 seconds
    }, 5000);
</script>

<div id="links"></div>

I am testing on my localhost, I do not get any response when I open the page

I have fixed the error, I debugged using google chrome, the code is correct but apparently i did not declare java script before the code