<div data-onload="sampleFunction('param1', 2)"></div>/* Find any element which has a 'data-onload' function and load that to simulate an onload. */
$('[data-onload]').each(function(){
eval($(this).data('onload'));
});window.onscroll = function(ev) {
if ((window.innerHeight + window.scrollY) >= document.body.offsetHeight) {
// you're at the bottom of the page
}
};//named functions
function timeTravel(year) {
console.log(this.firstName + " " + this.lastName + " is time traveling to " + year);
}//function expression
var someFn = function iHazName() {
console.log("I like to express myself...");
if(needsMoreExpressing) {
iHazName(); // the function's name can be used here
}
};
// you can call someFn() here, but not iHazName()
someFn();// The original array
var array = ["one", "two", "four"];
// splice(position, numberOfItemsToRemove, item)
array.splice(2, 0, "three");
array; // ["one", "two", "three", "four"]//using Prototype way
Array.prototype.insert = function (index, item) {
this.splice(index, 0, item);
};// Start with an initial array
var array = ["a", "b", "c"];
// Find and remove item from an array
var i = array.indexOf("b");
if(i != -1) {
array.splice(i, 1);
}Of course if you'd like to remove multiple occurrences of the same string/number:
for(var i = array.length-1; i--;){
if (array[i] === "b") array.splice(i, 1);
}//clone contents of array
var clone = myArray.slice(0); //the references are kept//deep clone
Array.prototype.clone = function() {
return this.slice(0);
};//Setting the length equal to zero empties the existing array, not creating another array!
myArray.length = 0; - Let's say you have an array of objects representing persons and you want to sort them by age
[
{ name: "Robin Van Persie", age: 28 },
{ name: "Theo Walcott", age: 22 },
{ name: "Bacary Sagna", age: 26 }
].sort(function(obj1, obj2) {
// Ascending: first age less than the previous
return obj1.age - obj2.age;
});
// Returns:
// [
// { name: "Theo Walcott", age: 22 },
// { name: "Bacary Sagna", age: 26 },
// { name: "Robin Van Persie", age: 28 }
// ]
-
As you may know JavaScript has types, like nodeList or the arguments variable within a function, that are similar to arrays, but not arrays. This means that we can access their elements using an array-like notations (for example arguments[0]) but we can’t use array methods such as forEach() and join().
-
Let’s say we have a nodeList of DOM elements retrieved as follows:
var list = document.getElementsByClassName('book');- We want to iterate over this array-like object using the forEach() method. If we call forEach() directly on the variable (list.forEach(...)) we obtain the error: “Uncaught TypeError: undefined is not a function”. To avoid this issue, one of the most used techniques is to use the prototype property and the call() method as shown below:
Array.prototype.forEach.call(list, function() {...});
//or
[].forEach.call(list, function() {...});- jQuery way:
$.makeArray(list).forEach(function() {...});;// When PhoneGap is loaded and talking with the native device,
// it will call the event `deviceready`.
//
document.addEventListener("deviceready", onDeviceReady, false);
// PhoneGap is loaded and it is now safe to make calls PhoneGap methods
//
function onDeviceReady() {
// Now safe to use the PhoneGap API
}Using console.log on objects which may change will throw you off.
This snippet prints out the object and its values at the immediate state
console.logNow = function(o){console.log(JSON.parse(JSON.stringify(o)));}; //for logging those objects that might change.
//viewmodel.js
var viewModel = kendo.observable({
mail: "[email protected]",
mailtoLink: function() {
return "mailto:" + this.get("mail");
}
})
kendo.bind($("#example"), viewModel)
//index.html
<div id="example">
<a data-bind="attr: { href: mailtoLink }">mail</a>
</div>
var doSomething = function (e) { console.log("Global"); }
var viewModel = kendo.observable({
doSomething: function (e) { console.log("ViewModel"); }
});
<div data-role="view" data-model="viewModel">
<span data-role="button" data-click="doSomething">
Clicking me will call doSomething() and print "Global"
</span>
<span data-role="button" data-bind="click: doSomething">
Clicking me will call viewModel.doSomething() and print "ViewModel"
</span>
</div>
var startDate = document.getElementById("BookingStartDate").valueAsDate; //grab a date object from user input
console.log(startDate);
console.log(kendo.toString(startDate, "yyyy-MM-dd" ));
$("body").data().kendoMobilePane.navigate("#:back");
function LogSomeStuff (obj) {
var output, property;
for (property in obj) {
output += property + ': ' + obj[property] + '; ';
}
console.log(output);
}
Object.defineProperty(obj, prop, descriptor) defineProperty method takes three arguments:
- The first is the object to add the property to
- second is the name of the property
- third is an object that describes the property (known as the property’s descriptor - has get,set optional keys)
You may also pass following keys:
- configurable (false by default): if this is true, the property’s configuration will be modifiable in future.
- enumerable (false by default): if true, the property will appear when looping over the object (for (var key in obj)).
var person = {
firstName: 'Jimmy',
lastName: 'Smith'
};
Object.defineProperty(person, 'fullName', {
get: function() {
return firstName + ' ' + lastName;
},
set: function(name) {
var words = name.split(' ');
this.firstName = words[0] || '';
this.lastName = words[1] || '';
}
});person.fullName = 'Jack Franklin';
console.log(person.firstName); // Jack
console.log(person.lastName) // FranklinWe can also define properties that don’t have explicit getters or setters:
Object.defineProperty(person, 'age', {
value: 42 //read-only property
});If a property has a value key set, it cannot have a getter or setter. Properties can have values or accessors, not both. this property will not appear when we loop over the object’s keys. If we wanted to make a property writable, we would need to set the writable property:
Object.defineProperty(person, 'age', {
value: 42, //Now, person.age = 99; will work.
writable: true
});<input id='phone' type="text" />
<script>
(function(){
$('#phone').kendoMaskedTextBox({
mask: '(999) 000-0000'
});
}());
</script>
<input id="fname" data-bind="value: firstName">
select element using console and write
$0in console
$0.kendoBindingTarget //this is where Kendo UI stores data about the binding that is attached to the element
object returned:
{
options: ,
source: , // the JavaScript object that we are bound to.
target: , // the HTML element, same as the one you already selected to get this far.
toDestroy: []
}
- $0.kendoBindingTarget.source.firstName; // see to what value is bound to, returns "John"
Advanced usage:
var kendoValueBinder = $0.kendoBindingTarget.toDestroy[1];
kendoValueBinder.source === kendoValueBinder.parents[0];
// returns true
function getKendoBindingValue(kendoBinder) {
var numParents = kendoBinder.parents.length;
var i = 0;
for(i = 0; i < numParents; i++) {
if(kendoBinder.path in kendoBinder.parents[i]) {
return kendoBinder.parents[i][kendoBinder.path];
}
}
return undefined; // not found.
}
$.getJSON('http://hipsterjesus.com/api/', function(data) {
$('body').append(data.text);
});or using promises:
var promise = $.getJSON('http://hipsterjesus.com/api/');
promise.done(function(data) {
$('body').append(data.text);
});
promise.fail(function() {
$('body').append('<p>Oh no, something went wrong!</p>');
});you can remove promise variable also:
$.getJSON('http://hipsterjesus.com/api/')
.done(function(data) {
$('body').append(data.text);
})
.fail(function() {
$('body').append('<p>Oh no, something went wrong!</p>');
})
//always event handler that's called regardless if the request succeed or fails.
.always(function() {
$('body').append('<p>I promise this will always be added!.</p>');
});creating wrapper object:
//THEN method allows us to modify the result of a promise and pass it to the next handler in the chain.
var wrapperObject = {
html: function() {
return $.getJSON('http://hipsterjesus.com/api/').then(function(data) {
return data.text;
});
}
};
//we can then use our wrapper object like this:
wrapperObject.html().done(function(html) {
$("body").append(html);
});adding method to object and chaining promises:
var wrapperObject = {
html: function() {
return $.getJSON('http://hipsterjesus.com/api/').then(function(data) {
return data.text;
});
},
//returns array of paragraphs
paragraphs: function() {
return this.html().then(function(html) {
return html.replace(/<[^>]+>/g, "").split("");
});
},
//the return value of a promise's callback is passed to the next callback in the chain,
//we're free to create small functional methods that change the data as it's passed through them.
sentences: function() {
return this.paragraphs().then(function(paragraphs) {
return [].concat.apply([], paragraphs.map(function(paragraph) {
return paragraph.split(/. /);
}));
});
}
};multiple API calls:
var firstData = null;
var secondData = null;
var responseCallback = function() {
if (!firstData || !secondData)
return;
// do something
}
$.get("http://example.com/first", function(data) {
firstData = data;
responseCallback();
});
$.get("http://example.com/second", function(data) {
secondData = data;
responseCallback();
});
//or using promises
var firstPromise = $.get("http://example.com/first");
var secondPromise = $.get("http://example.com/second");
$.when(firstPromise, secondPromise).done(function(firstData, secondData) {
// do something
});var marty = {
firstName: "Marty",
lastName: "McFly",
timeTravel: function(year) {
console.log(this.firstName + " " + this.lastName + " is time traveling to " + year);
}
}
marty.timeTravel(1955);
// Marty McFly is time traveling to 1955you can take the marty object’s timeTravel method and create a new reference to it from another object. enabling us to apply behavior (functions) to more than one target instance
var doc = {
firstName: "Emmett",
lastName: "Brown",
}
doc.timeTravel = marty.timeTravel;
doc.timeTravel(1885);
// Emmett Brown is time traveling to 1885
//when you’re invoking a method, the this context is the parent object it’s being invoked from.What happens when we save a reference to the marty.TimeTravel method and invoke our saved reference?
var getBackInTime = marty.timeTravel;
getBackInTime(2014);
// undefined undefined is time traveling to 2014Whenever a function is called, we must look at the immediate left side of the brackets / parentheses “()”. If on the left side of the parentheses we can see a reference, then the value of “this” passed to the function call is exactly of which that object belongs to, otherwise it is the global object.
The Value of this in Methods When Invoked Asynchronously:
var flux = document.getElementById("flux-capacitor");
flux.addEventListener("click", marty.timeTravel);
marty.timeTravel = function(year) {
console.log(this.firstName + " " + this.lastName + " is time traveling to " + year);
console.log(this);
};
flux.addEventListener("click", function(e) {
marty.timeTravel(someYearValue);
});
The Value of this Inside Constructor Functions:
var TimeTraveler = function(fName, lName) {
this.firstName = fName;
this.lastName = lName;
// Constructor functions return the
// newly created object for us unless
// we specifically return something else
};
var marty = new TimeTraveler("Marty", "McFly");
console.log(marty.firstName + " " + marty.lastName);
// Marty McFlyUsing Call, Apply & Bind
//The call and apply methods that exist on the Function prototype both allow us to invoke a function and pass in this value
someFn.call(this, arg1, arg2, arg3);
someFn.apply(this, [arg1, arg2, arg3]);
doc.timeTravelFor = function(instance, year) {
this.timeTravel.call(instance, year);
// alternate syntax if you used apply would be
// this.timeTravel.apply(instance, [year]);
};
var einstein = {
firstName: "Einstein",
lastName: "(the dog)"
};
doc.timeTravelFor(einstein, 1985);
// Einstein (the dog) is time traveling to 1985if (typeof cordova == "undefined") {
//it's html5
}
else {
//it's hybrid
} function googleTrackingPixel() {
// set google variables as globals
window.google_conversion_id = config.google_conversion_id
window.google_conversion_language = config.google_conversion_language
window.google_conversion_format = config.google_conversion_format
window.google_conversion_color = config.google_conversion_color
window.google_conversion_label = config.google_conversion_label
window.google_conversion_value = config.google_conversion_value
window.google_remarketing_only = config.google_remarketing_only
//bez ovoga ne radi
var oldDocWrite = document.write // save old doc write
document.write = function (node) { // change doc write to be friendlier, temporary
$("body").append(node)
}
$.getScript("http://www.googleadservices.com/pagead/conversion.js", function () {
setTimeout(function () { // let the above script run, then replace doc.write
document.write = oldDocWrite
}, 100)
})
}<% if(false)
{ %>
<script src="/path/to/vsdoc.js" type="text/javascript"></script>
<% } %>
or at the top of your .js file:
/// <reference path="/path/to/vsdoc.js" />
Sometimes you'll also need to press Ctrl + Shift + J to update javascript intellisense in visual studio
//normal function
function sayHello(){
alert('hello');
};//self-executing function
(function sayHello(){
alert('hello');
})();##Sharing properties using prototype chains
//ecma6 way
var PersonProto = {
describe: function() {
return 'Person named ' + this.name;
}
};
var jane = {
__proto__: PersonProto,
name: 'Jane'
};
var tarzan = {
__proto__: PersonProto,
name: 'Tarzan'
};
jane.describe() //Person named Jane//ecma5 way
var jane = Object.create(PersonProto);
jane.name = 'Jane';//Sharing methods
//Instance-specific properties
function Person(name) {
this.name = name;
}
//shared properties
Person.prototype.describe = function() {
return 'Person named' + this.name;
};##Inheritance between constructors
//Superconstructor
function Person(name) {
this.name = name;
}
Person.prototype.sayHelloTo = function(otherName) {
console.log(this.name + ' says hello to ' + otherName);
};
Person.prototype.describe = function () {
return 'Person named ' + this.name;
};Employee must:
- inherit Persons instance properties
- create the instance property title
- inherit Persons prototype properties
- override method Person.prototype.describe and call overridden method (super-call)
//Subconstructor
function Employee(name, title) {
Person.call(this, name); //1.
this.title = title; //2.
}
Employee.prototype = Object.create(Person.prototype); //3.
Employee.prototype.describe = function() { //4.
return Person.prototype.describe.call(this) //5.
+ ' (' + this.title + ')';
};
//test
var jane = new Employee('Jane', 'CTO');
jane.name;
jane.title;
Object.keys(jane);
jane.sayHelloTo('Alex');
jane.describe();##jQuery selectors
$("#item") // select an element with the id of "item"
$(".fancybutton") // select an element with a class of "fancybutton"
$("li:even") // select the even numbered items in a list
$("ul li:nth-child(3)") // select the 3rd list item in an unordered list- [more selectors] (http://flippinawesome.org/2014/05/12/rethinking-dom-traversal/?utm_source=rss&utm_medium=rss&utm_campaign=rethinking-dom-traversal)
##Notification Widget - Kendo UI
<span id="popupNotification"></span>var popupNotification = $("#popupNotification").kendoNotification().data("kendoNotification");
popupNotification.show("Hey there!", "info");##Remove element from HTML
function removeElement(ele) {
ele.parentNode.removeChild(ele);
}
removeElement(document.getElementById("image_X"));
//can apply display:none or visibility:hidden to hide img outline//set src to empty
$('#img').attr('src', '');##Closing browser tab
open(location, '_self').close();##Remove image with specific src attribute
$(document).ready(function() {
$("img").each(function() {
if($(this).attr("src") == "testImage.png") {
$(this).remove();
//Or you can use
$(this).hide();
//Or you can use
$(this).css("display", "none");
}
});
});##Change Image Source Attribute of all images belonging to a specific Class in jQuery
$('#change_src').click(function() {
$('.img_class').each(function(){
$(this).attr('src','somedir/some_image_name.jpg');
});
});##Change Size / Style Attribute of all Images belonging to a specific Class in jQuery
$('#change_src').click(function() {
$('.img_class').each(function(){
//Check if the style attribute is already defined. If yes, then get that value
if($(".img_class[style]").length)
{
var current_style = $(this).attr('style');
}
else
{
//Assign empty value
var current_style = '';
}
$(this).attr('style','width:150px;' + current_style);
});
});##Select all elements with id that contains string:
$(document).ready(function(){
$('#test').click(function(){
$('div[id^="Some_id_"]').each(function()
{
$(this).css('color','blue');
});
});
});##Convert HTML to text:
- Content without dashes, ampersands and other punctuation codes
var text = html.replace(/<\/?[^>]+>/ig, " ");- Workaround
var temp = document.createElement("div");
temp.innerHTML = html;
return temp.textContent || temp.innerText || "";##Make div clickable if there is link text
$(function(){
$("div").click(function(){
window.location=$(this).find("a").attr("href");
return false;
});
});##A One-Time Event Creation Function
// create a one-time event
function onetime(node, type, callback) {
// create event
node.addEventListener(type, function(e) {
// remove event
e.target.removeEventListener(e.type, arguments.callee);
// call handler
return callback(e);
});
}Using function:
// one-time event
onetime(document.getElementById("myelement"), "click", handler);
// handler function
function handler(e) {
alert("You'll only see this once!");
}