js生成隨機的不重復多位數字, 用于驗證碼
function getRandum(num,arr){ var str = ""; for(var i = 0; i < num ; i++){ var n = Math.floor(Math.random() * arr.length); if(str.indexOf(arr[n]) != -1){ i--; } else{ str += arr[n]; } } return str; } var arr = [0,1,2,3,4,5,6,7, 8, 9, "A","B","c","D","E","F","G","H"]; console.log(getRandum(4,arr))