javascript - 如何在特定时间后自动运行 Ajax 请求？

Question

我有一个 Ajax 函数 (ajaxRequest)，我想在某个特定时间(比如 5 秒)后自动运行，而无需任何用户提示或警告。我怎样才能做到这一点？ (我查看了以下链接但没有找到解决方案)

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//My Code
//ajaxRequest Script..

<script type="text/javascript">
function ajaxRequest(map){

var xmlhttp = new XMLHttpRequest();
xmlhttp.open("GET", 'json_data.php', true);

xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
    var myArr = JSON.parse(xmlhttp.responseText);
    setMarkers(map,myArr);
}
};
xmlhttp.send(null);
}
</script>

<script>
function myMap() {
var mapCanvas = document.getElementById("map");
var myCenter = new google.maps.LatLng(51.508742,-0.120850);
var lat=51.508742;
var lng=-0.140850;
var mapOptions = {center: myCenter, zoom: 5};
var map = new google.maps.Map(mapCanvas,mapOptions);

ajaxRequest(map);                                   //Called ajaxRequest

}
</script>

Answer 1

如果你想执行你的代码，你可以使用setTimeout() ，如果你想每 x 秒执行一次你的代码，你可以使用 setInterval() .

setTimeout(function() {
    //The code you want to execute after 5 seconds
}, 5000);
//OR
setInterval(function() {
    //The code you want to execute every 5 seconds  
}, 5000);