some useful pieces of code in JS

gistfile1.txt

1.Get a random item from an array
  var arr = [1, 2, 3, 4, 5];
  var item = arr[Math.floor(Math.random() * arr.length)];
  
2.Get a random number in a specific range
  var item = Math.floor(Math.random() * (max - min + 1)) + min;
  
3.Generate a random set of alphanumeric characters
  function generate(len) {
    var randomString = "";
    for(; randomString.length < len; randomString += Math.random().toString(36).substr(2));
    
    return randomString.substr(0, len);
  }
  
4.Generate an array of numbers with numbers from 0 to max
  var numberArr = [], max = 100;
  for(var i = 1; numberArr.push(i++) < max; ;);
  
5.A string trim function
  String.prototype.trim = function(){return this.replace(/^\s+|\s+$/g, "");};
  
6.Append an array to another
  var arr1 = [1, 2, 3];
  var arr2 = [4, 5, 6];
  Array.prototype.push.apply(arr1, arr2);
  
7.Transform the arguments object to array
  var argArray = Array.prototype.slice.call(arguments);
  
8.Verify that a given argument is a number
  function isNumber(n) {
    return !isNaN(parseFloat(n)) && isFinite(n);
  }