js面试总结

<div id="app">
    <button onClick="app()">点击1</button>
    <button onClick="app1()">点击2</button>
</div>

<script>
function app () {
  console.log(this);
}
function app1 () {
    app();} 

app();

</script>

非严格模式下，打印window;   [object Window],  

严格模式下，打印undefined