Scopes in Javascript

   window.color = “red”; //<-- general scope everything without a scope
   var object = { color: “blue” };
   function sayColor(){
     //alert(this.color);
   }
   sayColor(); //”red” without scope
   o.sayColor = sayColor;
   o.sayColor(); //”blue” inside a object/function

Function Declarations vs. Function Expressions

A Function Declaration is:

function add(numberOne, numberTwo){
    return numberOne + numberTwo;
}

A Function Expressions is:

var add = function(numberOne, numberTwo){
      return numberOne + numberTow;
};

When we write a function declaration, it's loaded in the execution context, before the script runs, but when we write a function expresion, the interpreter, load while it's executing the code. So we can find a simple error.

//alert(add(10,10)); the vm doesn't found the function add(), because it's not loaded
var add = function(numberOne, numberTwo){
      return numberOne + numberTow;
};

My first Class in Javascript: Manage the Html tag select

//objeto que describe cada uno de los 
//options del Select|Combo
function ComboOption(texto, valor) {
    this.texto = texto;
    this.valor = valor;
}

//Gestiona las posibles operaciones sobre el control
//HTML 
function GestorCombo(idCombo) {
    this.combo = document.getElementById(idCombo);
    if (this.combo == null) { return; }

    this.borrarTodasLasOpciones = function () {

        var i;
        for (i = this.combo.length - 1; i >= 0; i--) {
            if (this.combo.options[i].selected) {
                this.combo.remove(i);
            }
        }
    }

    this.aniadirOption = function (option) {
        this.combo.options[this.combo.options.length] = new Option(option.texto, option.valor);
    }

    this.conseguirValorSeleccionado = function () {
        var resultado = '';
        if ((this.combo.selectedIndex > -1) && (this.combo.options.length > 0)) {
            resultado = this.combo.options[this.combo.selectedIndex].value;
        }
        return resultado;
    }

    this.seleccionarOption = function (valor) {
        for (i = 0; i < this.combo.options.length; i++) {
            if (this.combo.options[i].value == valor) { break; } 
        }
        this.combo.options.selectedIndex = i;
    }
}

Brian Crain

A new piano author appears in my life, he's Brian Crain some music of him.
Happy listening!!!

Ordering Asc & Desc In Javascript

It's aMazing and so easy!!! Here it's the code

  function orderDescending(valueOne, valueTwo){
   if(valueTwo > valueOne){
    return 1;
   }
   if (valueTwo < valueOne) {
    return -1;
   }
   else{return 0;}
  }
  function orderAscending(valueOne, valueTwo){
   if(valueTwo > valueOne){
    return -1;
   }
   if (valueTwo < valueOne) {
    return 1;
   }
   else{return 0;} 
  }

  var numbers = [1,4,27,4,8,0];

  numbers.sort(orderAscending);
  //alert(numbers);

  numbers.sort(orderDescending);
  //alert(numbers);

But We can improve it, in this way ...

function Comparator(propertyName) {
   return function(objectOne, objectTwo){
   var valueOne = objectOne[propertyName];
   var valueTwo = objectTwo[propertyName];
   if (value1 < value2){
     return -1;
   } else if (value1 > value2){
      return 1;
   } else {
      return 0;
   }
   };
}

And We can use it in this way

var data = [{name: “PersonOne”, age: 1}, {name: “PersonTwo”, age: 2}];
data.sort(Comparator(“name”));

Working With JQueryDataTable data

I´m using JQuery-DataTable in a SharePoint 2010 Application. 
I comunicate server to client throught $.getJSON(url, parameter, function(returnData){});
But when I pass the JSON to JQueryDatatable, it doesn´t work, why? I don´t Know.
It works, with arrays, not with objects, I don´t why. 
But we must convert the JSON Object into Array. So We have to use this simple function

function ConvertObjectToArray(obj) {
        var arr = [];

        for (cont = 0; cont < obj.length; cont++) {
            var t = 0;
            arr[cont] = [obj.length];

            for (var propiedad in obj[cont]) {
                arr[cont][t] = obj[cont][propiedad];
                t++;
            }
        }

        return arr;
    }

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