javascript - Javascript 异步函数调用中 setInterval 函数异常

Question

下面是我准备构建网站的代码片段。

<小时/>

<script type="text/javaScript">
    function h(d) {
console.log("hello");
return;

};



function func(callback) {
var httpRequest; // create our XMLHttpRequest object
if (window.XMLHttpRequest) {
    httpRequest = new XMLHttpRequest();
} else if (window.ActiveXObject) {
    // Internet Explorer old versions
    httpRequest = new
        ActiveXObject("Microsoft.XMLHTTP");
}

httpRequest.onreadystatechange = function() {
    // inline function to check the status      
    if (httpRequest.readyState === 4 &&
            httpRequest.status === 200) {
        callback(httpRequest.responseText);

        // call the callback function
    }
};
httpRequest.open("GET", '/try_ajax',true);
httpRequest.send();
}
// call the function
setInterval(func(h), 10000); // Timer is triggered here


</script>

<小时/>

有趣的是，虽然我将间隔设置为 10 秒，但在我的控制台中“hello”仅出现一次。但 10 秒后它应该会继续出现。请帮忙!

Answer 1

这是错误的

setInterval(func(h), 10000); // Timer is triggered here

您的意思是获取从 func(h) 返回的任何内容并将其分配给超时

setInterval(function(){func(h);}, 10000); // Timer is triggered here