<!DOCTYPE html> <html> <body> <h2>JavaScript Number 方法</h2> <p>toPrecision() 返回字符串,其中包含指定长度的数字:</p> <p id="demo"></p> <script> let x = 9.656; document.getElementById("demo").innerHTML = x.toPrecision() + "<br>" + x.toPrecision(2) + "<br>" + x.toPrecision(4) + "<br>" + x.toPrecision(6); </script> </body> </html>