javascript实现随机读取数组的方法

function write_quote() {  var quotes = [    'no animals were harmed while making this page',    'made in ulm',    'this page was handmade',    'Get <a href="http://www.mozilla.org/products/firefox/">FireFox</a> :-)'  ];  var r = Math.round(Math.random() * (quotes.length-1));  // write the quote  document.write(quotes[r]);  // or replace an HTML element:  // document.getElementById("quote").innerHTML = quotes[r];}