下面这个函数是js查找一篇英文文章中出现频率最高的单词(由26个英文字母大小写构成)，输出该单词及出现次数，不区分大小写，主要是正则的运用：
function counts(article){ article = article.trim().toUpperCase(); var array = article.match(/[A-z]+/g); article = " "+array.join(" ")+" "; var max = 0,word,num = 0,maxword=""; for(var i = 0; i < array.length; i++) { word = new RegExp(" "+array[i]+" ",'g'); num = article.match(word).length; if(num>max){ max=num; maxword = array[i]; } } console.log(maxword+" "+max); } counts("Age has reached the end of the beginning of a word. May be guilty in his seems to passing a lot of different life became the appearance of the same day;");