我是OnScreen的作者，它是一个小型库，可以在HTMLElement进入视口或其容器的边界时调用回调函数./p>

I'm the author of OnScreen, a small library that can call a callback function when a HTMLElement enters the viewport or the boundaries of its container.

// Uses ES6 syntax
import OnScreen from 'onscreen';

const os = new OnScreen();

os.on('enter', 'canvas', (element) => {
    if (!element.chartInitialized) {
        // Initialize the chart

        // Update the `chartInitialized` property
        // to avoid initializing it over and over
        element.chartInitialized = true;
    }
});

有关更多信息，请查看文档 .不要忘记查看 demos存储库中的几个简单示例.

For more information, take a look at the documentation. Don't forget to check the demos repo for a couple simple examples.