<!DOCTYPE html> <html> <body> <h1>JavaScript 字符串</h1> <h2>charAt() 方法</h2> <p>charAt() 返回字符串中指定索引(位置)处的字符。</p> <p>默认索引为 0:</p> <p id="demo"></p> <script> let text = "HELLO WORLD"; let letter = text.charAt(); document.getElementById("demo").innerHTML = letter; </script> </body> </html>