Skip to main content

javascript: functions

Creating a function
function isNimble(){ return true; } 
var canFly = function(){ return true; }; 
window.isDeadly = function(){ return true; }; 

function call by itself
 function hello(n){
    return n>0? hello(n-1)+"a":"hiy";    

if you don't want to give function name
function  hello(n){
    return n>0?arguments.callee(n-1)+"a":"hiy";    

Named Functions
function hello(){return "hiyaa";}

 //what is the name of the function ?

 var emp = function myEmp(){return "emp";};
Functions as Objects
//Normal JavaScript Object
var obj = {}; 

//Simple function declarication
var fn = function(){};

//both has properties
obj.prop = "some value"; 
fn.prop = "some value";  
//other existing properties in function -> length, call, apply

 //without cache
function isPrime( num ) { 
  var prime = num != 1; // Everything but 1 can be prime 
  for ( var i = 2; i < num; i++ ) { 
    if ( num % i == 0 ) { 
      prime = false; 
  return prime; 

//with cache
function isPrime( num ) { 
  if ( isPrime.cache[ num ] != null ) 
    return isPrime.cache[ num ]; 
  var prime = num != 1; // Everything but 1 can be prime 
  for ( var i = 2; i < num; i++ ) { 
    if ( num % i == 0 ) { 
      prime = false; 
  isPrime.cache[ num ] = prime;   
  return prime; 
//static object of function which hold the cache data 
isPrime.cache = {}; //static object of the function
->isPrime(5); //true


Popular posts from this blog

ERROR: Ignored call to 'alert()'. The document is sandboxed, and the 'allow-modals' keyword is not set.

Recently I found this issue while writing code snippet in "JSFiddle". And after searching, found this was happening because of new feature added in "Chrome 46+". But at the same time Chrome doesn't have support for "allow-modals" property in "sandbox" attribute.

Chromium issue for above behavior:

To make it work you have to add "allow-scripts allow-modals" in "sandbox" attribute, and use "window.alert" instead of "alert".

<!-- Sandbox frame will execute javascript and show modal dialogs --> <iframe sandbox="allow-scripts allow-modals" src="iframe.html"> </iframe>

Feature added: Block modal dialog inside a sandboxed iframe.

Feature working Demo page:

JavaScript [ExtJs3]: EditorGridPanel Read-Only (dynamically)

Many time we face the scenerio where we have to make the editor grid read-only dynamically.

Ext.override(Ext.ux.grid.CheckColumn, { editable: true, onMouseDown: function (e, t) { if ( { e.stopEvent(); var me = this, grid = me.grid, view = grid.getView(), index = view.findRowIndex(t), colindex = view.findCellIndex(t), record =; if (!grid.isReadOnly && grid.colModel.isCellEditable(colindex, index)) { record.set(me.dataIndex, ![me.dataIndex]); } } } }); var grid = new Ext.grid.EditorGridPanel({ ... isReadOnly: true, //set to flag to make check column readonly ... }); //to make other column readonly grid.on('beforeedit', function () { return false; });

JavaScript [ExtJs3]: Total “Record” count in filtered store

There is two way to get record count from the Store
store.getTotalCount() This function depend on server response value. For accuracy of the value, property shell if return by the server.

Property name for the diff. reader:
totalProperty for JsonReader, totalRecords for XmlReaderstore.getCount() Will return you the number of record from the store.
Or if you have filter on the store, it will give you the number of filtered record.
But if you want to get the total number of record regardless filtering, Then it will be like this

var totalRecords = store.snapshot ? store.snapshot.length : store.getCount();
“snapshot” is the variable in “Store” which hold the actual data in case if you have applied a filter.