JavaScript 变量定义 JavaScript 空数组 JavaScript 检查未定义变量 JavaScript 变量定义 <html> <head> <title>JavaScript Arrays</title> </head> <body> <script> var arr = ["orange", "mango", "banana", "sugar", "tea"]; document.write("<br />Original array: " + arr ); arr = []; document.write("<br />Current array: " + arr ); </script> </body> </html> JavaScript 空数组 JavaScript 检查未定义变量