How to use asynchronous functions? Summarize the usage of asynchronous function examples

Study a small question today: How to get the return value of a JavaScript asynchronous function? 1. Wrong attempt When I didn’t enter the industry that year, my initial attempt was: <script> function getSomething() { var r = 0; setTimeout(function() { r = 2; }, 10); return r; } function compute() { var x = getSomething(); alert(x * 2); } compute(); </script>2. The callback function pops up is not 4, but

1. How to get the return value of JavaScript asynchronous function

Introduction: Let’s study a small question today: How to get the return value of a JavaScript asynchronous function? 1. Wrong attempt When I was not in the industry, my initial attempt was: