The de-weight of the array, and a random verification code

The de-weight of an array

The code is as follows:

  var arr=[1,1,1,12,2,3,4,4,5];  
  function Quchong (arrtest) { 
  var Arrkong=[]; var an empty array that stores the content that is not duplicated  
  for (Var i=0;i<=arrtest.length;i++) {//  Iterate through each element in the array  
  if (Arrkong.indexof (Arrtest[i]) <0) {//will not duplicate elements, i.e. indexOf  The number of <0 is removed  
  Arrkong.push (Arrtest[i]);      Use the push method to place the non-repeating elements into the new array  
 "  
  
  return arrkong;//return value is new array  
 
 }  
 
 document.write (Quchong (arr)); The result is 1.12,2,3,4,5  
 
 
 
  II production random verification code  
 
 

var str1= ' abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz0123456789-_ ';  Determine the scope of the Verification code
        function Suiji (n) {
            var str= '; var an empty string that stores randomly generated characters
            for (Var i=0;i<n;i++) {  //number of characters required, loop
                var Num=math.floor (Math.random () *str1.length); Random string angle Index by random number method
                Str+=str1.substring (num,num+1); The resulting string is mapped to the contents of the string and stored in a new string of the previous Var
            } return str; Returns a new string
        }
    Console.log (Suiji (5));

The de-weight of the array, and a random verification code