Failed to execute ‘requestFullscreen‘ on ‘Element‘

来源：http://www.shanhubei.com/archives/13628.html

浏览器无法自启动全屏模式
报错信息：Failed to execute ‘requestFullscreen’ on ‘Element’: API can only be initiated by a user gesture.
翻译：无法在element上执行requestFullscreen方法，这个API只有用户主动行为才可以触发。

    window.onload = () => {
        let element = document.documentElement
        if (element.requestFullscreen) {
                element.requestFullscreen()
            } else if (element.msRequestFullscreen) { // 兼容ie
                element.msRequestFullscreen()
            } else if (element.mozRequestFullScreen) { // 兼容火狐
                element.mozRequestFullScreen()
            } else if (element.webkitRequestFullscreen) { // 兼容chrome和safari
                element.webkitRequestFullscreen()
            }
        }
    }