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<!DOCTYPE html> <html> <body> <p>单击这个按钮可按降序循环遍历数组的索引。</p> <button onclick="myFunction()">Try it</button> <p id="demo"></p> <script> function myFunction() { var cars = ["BMW", "Volvo", "Saab", "Ford"]; var text = ""; var len = cars.length; while (len--) { text += cars[len] + "<br>"; } document.getElementById("demo").innerHTML = text; } </script> </body> </html>