Question

好的，我在下面有这个函数，我每5秒钟调用一次..

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       

}

我每隔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fail被执行，那么它显然会每隔5秒继续执行一次，因为它不会离开页面。

如果出现问题，我怎样才能让它只显示一次警报？

Answer 1

保留对间隔的引用，并在间隔失败时将其清除。

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.');
});

Answer 2

不确定这是否是最好的方法，但是动态创建dom元素并检查其存在是否有效，您甚至可以检查其值并更改它们以执行任何其他操作;所以基本上它作为一个标志，如果需要可以作为其他事件触发的条件检查器：

.fail(function() {
    // create a hidden element in dom to check for the alert event execution
    if ($('#errorchecker').length === 0) {
        $('body').append('<input type="hidden" id="errorchecker" value="executed" />');
        alert('There seems to have been a problem with continuing the verification process; please contact us if this continues to occur.');
    }        
});

如何通过AJAX重复调用函数来阻止警报多次显示？

2 个答案: