javascript - 为什么 settimeout() 匿名函数不调用 JavaScript 中的函数？

Question

我在下面编写代码来调用外部 Web 服务，如果没有调试器，它在 safari 浏览器中不起作用。因此作为解决方案，我添加了 settimeout() 函数来延迟 xhr.send() 函数。真正的问题如下所述:
我试图在 2 秒后调用alertFunc，但 settimeout() 函数没有调用alertFunc。你能帮我解决这个问题吗？我在下面的代码中定义了我的 WordPress footer.php 文件。

<script type="text/javascript">
debugger;
var xhr;
      // Create the XHR object.
      function createCORSRequest(method, url) {

           xhr = new XMLHttpRequest();
           if ("withCredentials" in xhr) {
             // XHR for Chrome/Firefox/Opera/Safari.

        xhr.open(method, url, true);


           } else if (typeof XDomainRequest != "undefined") {
             // XDomainRequest for IE.
             xhr = new XDomainRequest();
             xhr.open(method, url);
           } else {
             // CORS not supported.
             xhr = null;
           }
           return xhr;
         }

    function alertFunc(xh) {
        debugger;
           var xh1=xh;
           xh1.send();
       alert("Thank you for contacting us!");

    }
        function saveContactData() {
            var name = document.getElementById('name').value;
            var petname = document.getElementById('petname').value;
            var weight = document.getElementById('weight').value;
             var breed = document.getElementById('breed').value;
            var phone = document.getElementById('phone').value;
            var email = document.getElementById('email').value;
            var findus = document.getElementById('findus').value;
            var location = document.getElementById('location').value;
            var comments = document.getElementById('comments').value;



            var item = {
                "PetInquiryId": -1,
                "ClientName": name,
        "Weight":weight,
                "Breed":breed,
                "PhoneNumber": phone,
                "PetName": petname,
                "Email": email,
                "Comments": comments,
                "Location": location,
                "FindUsName": findus,

            };
        debugger;
             var url = "http://sitename/api/Controllername/functionnme?item=" + JSON.stringify(item);
            var xhr = createCORSRequest("POST",url);   

        //xhr.send();
         setTimeout(alertFunc(xhr), 25000);


       document.getElementById("myForm").reset();


        }


    </script>

Answer 1

用闭包包裹:

setTimeout(function(){alertFunc(xhr);}, 25000);