JS判断一个字符串是否含有重复字符
JS判断一个字符串是否含有重复字符，并且将结果排序：

function fun(){var str = "DCF";var arrays = new Array();var flag = true;for(var i=0;i<str.length;i++){var temS = str.charAt(i);if(str.replace(temS,"").indexOf(temS) > -1){flag = false;break;}arrays.push(temS);}if(flag){str = arrays.sort().join("");}else{str = "";}alert(str);}