Jquery如何在页面加载时启动功能并等待5秒？

Question

我需要在加载页面后5秒内自动启动函数snap。

我是怎么做到的？

完整代码原则上可以从视频文件中获取快照

<span id="snap" onclick="snap()" style="color:red">Take Screenshot</span>

<script>
var video = document.querySelector('video');
var canvas = document.querySelector('canvas');
var context = canvas.getContext('2d');
var w, h, ratio;

video.addEventListener('loadedmetadata', function(){
ratio = video.videoWidth / video.videoHeight;

w = video.videoWidth - 0;
h = parseInt(w / ratio, 0);
canvas.width = w;
canvas.height = h;

var a = "canvas.height";

}, false);


function snap(){
context.fillRect(0, 0, w, h);
context.drawImage(video, 0, 0, w, h);
};
</script>

Answer 1

添加：

setTimeout(function(){ 
    snap();
}, 5000);