javascript - 如何阻止通过 AJAX 重复调用某个函数时多次显示警报？

Question

好的，我在下面有这个函数，我每 5 秒调用一次..

function checkVerfToken(user_id) {

    // Set file to get results from..
    var loadUrl = "ajax_files/check_verf_token.php";

    // Set parameters
    var dataObject = { user_id: user_id };

    // Run request

    getAjaxData(loadUrl, dataObject, 'POST', 'html')

        .done(function(response) {

            if (response == 'success') {
                // Reload the page
                window.location.replace('payment_completed_verf.php');
            }

        })

        .fail(function() {
            alert('There seems to have been a problem with continuing the verification process; please contact us if this continues to occur.');
        });

    // End       

}

我每 5 秒从一个页面调用它:

<script type="text/javascript">
    window.setInterval(function(){
      checkVerfToken(<?=$user_id?>);
    }, 5000);
</script>

但是，如果执行 fail ，那么它显然会每 5 秒执行一次，因为它不会离开页面。

如果出现问题，如何让它只显示一次警报？

Answer 1

保留对间隔的引用，并在失败时清除它。

verifyInterval = window.setInterval(function(){
    checkVerfToken(<?=$user_id?>);
}, 5000);

.fail(function() {
    clearInterval(verifyInterval);
    alert('There seems to have been a problem with continuing the verification process; please contact us if this continues to occur.');
});