源代码
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>享学课堂</title> </head> <body> <h1>JavaScript 数组</h1> <p>在数组里在高索引添加新元素，能创建一个undefined "漏洞".</p> <p id="demo"></p> <script> var fruits, text, fLen, i; fruits = ["Banana", "Orange", "Apple", "Mango"]; fruits[6] = "Lemon"; fLen = fruits.length; text = ""; for (i = 0; i < fLen; i++) { text += fruits[i] + "<br>"; } document.getElementById("demo").innerHTML = text; </script> </body> </html>
运行结果