I have a lot of places in my application where I need to execute JS function and also bind it to some jquery event like "change" or "click". For refactoring purposes I'd like to create a generic function that should help me accomplish this. Here are my original thoughts:
function execute_and_track(trackEvent, action) {
action();
trackEvent(function () {
action();
});
}
And I thought to use it like this:
execute_and_track($("#ddl_Test").change, function () {
if ($("#ddl_Test").val().toUpperCase() == "OTHER") {
document.getElementById("txt_Test").style.display = "inline";
}
else {
document.getElementById("txt_Test").style.display = "none";
$("#txt_Test").val("");
}
});
Unfortunately this throws an error: Uncaught TypeError: Object [object global] has no method 'on'. It looks like I am not able to pass jquery change as a parameter. Can anybody help me to fix this logic or suggest another way of creating generic function for such refactoring?
If I understand the question, I would change approach.
Try this new one (as jquery plugin)
$.fn.execute_and_track = function(eventName, func) {
this.each(function() {
func.call(this); // fix the scope
$(this).on(eventName,func);
});
return this;
}
$("#ddl_Test").execute_and_track('change', function() {
if ($(this).val().toUpperCase() == "OTHER") {
this.style.display = "inline";
}
else {
this.style.display = "none";
$(this).val("");
}
});
Related
So I have the following jQuery code that I've built out that checks whether a on change event has been triggered on #rtk5 and then either removes or adds the 'required' attribute.
Works perfectly in jQuery:
// Make checkbox textboxes not required unless checked
$(document).ready(function() {
$('#rtk5').change(function() {
if ($('.rtk5ReqField').attr('required')) {
$('.rtk5ReqField').removeAttr('required');
}
else {
$('.rtk5ReqField').attr('required','required');
}
});
});
I would like to convert it to JavaScript with a function call, but I can't seem to figure out how to properly do it.
Error:
TypeError: rtk5req.getAttribute is not a function
Here is my attempt:
var rtk5req = document.getElementsByClassName('rtk5ReqField');
function rtk5Required() {
rtk5req.addEventListener('change', (e) => {
if (rtk5req.getAttribute('required')) {
rtk5req.removeAttribute('required');
} else {
rtk5req.getAttribute('required', 'required');
}
});
}
rtk5req.addEventListener('change', rtk5Required());
document.addEventListener('DOMContentLoaded', rtk5Required);
rtk5Required();
Updated code: Removed the repetitive change call
var rtk5req = document.getElementsByClassName('rtk5ReqField');
function rtk5Required() {
if (rtk5req.getAttribute('required')) {
rtk5req.removeAttribute('required');
} else {
rtk5req.getAttribute('required', 'required');
}
}
rtk5req.addEventListener('change', rtk5Required());
document.addEventListener('DOMContentLoaded', rtk5Required);
rtk5Required();
Updated code #2:
Thanks all for all the hard work, there's one small issue that I'm still experiencing and had to make some tweaking - When I uncheck the checkbox, it doesn't remove the required tag placed on rtk5Declaration from which it did in the jQuery.
var rtk5_selection = document.getElementById('rtk5');
document.addEventListener('DOMContentLoaded', () => {
rtk5_selection.addEventListener('change', () => {
if (rtk5_selection.getAttribute('required')) {
document.getElementById('rtk5Declaration').removeAttribute('required');
} else {
document.getElementById('rtk5Declaration').setAttribute('required', 'required');
}
});
});
Thanks so much all!
Since you only have one element you should be using its ID instead of its class, and avoiding the complication caused by document.getElementsByClassName returning a pseudo-array of elements instead of a single element.
NB: use setAttribute to change an attribute's value, or better yet (as shown in the code below) use the direct boolean property that mirrors the element's attribute.
document.addEventListener('DOMContentLoaded', () => {
const rtk_sel = document.getElementById('rtk5');
const rtk_dec = document.getElementById('rtk5Declaration');
rtk_sel.addEventListener('change', () => {
rtk_dec.required = !rtk_sel.checked;
});
});
Thanks all for the contribution, below is the working version which I have tweaked:
var rtk5_selection = document.getElementById('rtk5');
var rtk5declaration = document.getElementById('rtk5Declaration');
function rtd3Declaration() {
if (!rtk5_selection.checked) {
rtd3declaration.removeAttribute('required');
} else {
rtd3declaration.setAttribute('required', 'required');
}
}
rtk5_selection.addEventListener('change', rtd3Declaration);
document.addEventListener('DOMContentLoaded', rtd3Declaration);
rtd3Declaration();
I'm using the iteminvokedHandler and was wonder if there is a better way to interact with the listView.
Currently using this:
WinJS.UI.processAll(root).then(function () {
var listview = document.querySelector('#myNotePad').winControl;
listview.addEventListener("iteminvoked", itemInvokedHandler,false);
function itemInvokedHandler(e) {
e.detail.itemPromise.done(function (invokedItem) {
myEdit();
});
};
});
The problem is that everytime I click on the listview myEdit() is run and propagates within the listview. I was wondering how to do it once and stop invoking listview until I am done with myEdit? Is there a simpler way to handle such a situation as this?
Simple yet hard to see when you have a mind block and forget some of the basics (yes yes I'm still learning):
var testtrue = true;
WinJS.UI.processAll(root).then(function () {
var listview = document.querySelector('#myNotePad').winControl;
listview.addEventListener("iteminvoked", itemInvokedHandler,false);
function itemInvokedHandler(e) {
e.detail.itemPromise.done(function (invokedItem) {
if (testtrue === true){
myEdit();
}
});
};
});
In myEdit:
function myEdit() {
var theelem = document.querySelector(".win-selected #myNotes");
var gestureObject = new MSGesture();
gestureObject.target = theelem;
theelem.gestureObject = gestureObject;
theelem.addEventListener("pointerdown", pointerDown, false);
theelem.addEventListener("MSGestureHold", gestureHold, false);
function pointerDown(e) {
e.preventDefault();
e.target.gestureObject.addPointer(e.pointerId);
}
function gestureHold(e) {
if (e.detail === e.MSGESTURE_FLAG_BEGIN && test === true) {
e.preventDefault();
editNotes();
} else {
}
console.log(e);
}
theelem.addEventListener("contextmenu", function (e) {
e.preventDefault();}, false); //Preventing system menu
};
function editNotes() {
//The Code I wish to execute
return test = false;
};
What I needed was a conditional statement so that it would run if true and not if false. That same test needed to be done in the gestureHold otherwise it would continue to fire myEdit on the invoked item because of the way the gesture is attached to the item the first time it is run.
Here is the block of code I want to replace:
$(document).ready(function () {
$(".button-purple").click(function () {
interval = $(this).attr('id');
name = $(this.attr('name');
if(Number($(this).val()) === 0) {
if(name == 'static') {
do this
}
else {
do this
}
}
else {
do this
}
});
});
I can't find any documentation on trying to replace the function since it's unnamed though. Is it possible to replace the entire javascript file + delete the line loading it / insert my own script? Would really appreciate any help I can get.
If you just want to remove the click event handler, then simply say
var $element = $(".button-purple");
$element.off('click');
If you want to Remove all the event handlers, then you'll first have to find out what all event handlers are present and then remove them iteratively.
var element = $element[0]; //Make sure the element is a DOM object and not jQuery Object.
// Use this line if you're using jQuery 1.8+
var attachedEvents = $._data(element,'events');
// Use this line if you're using jQuery < 1.8
var attachedEvents = $(element).data('events'); //Here you can also replace $(element) with $element as declared above.
for(var event in attachedEvents){
$element.off(event);
}
UPDATE:
You can simply add your own event handler (using .on() API) after you're done removing all the required existing handlers.
Just define your function.
function yourFunction(){ /* your code */};
$element.on('click', yourFunction);
Update 2:
Since you just want to remove the click event handler, this is the simplest code that will serve your purpose.
$(".button-purple").off('click').on('click', yourFunction);
I'm not aware of tampermonkey, but you can try this:
function chickHandler() {
interval = $(this).attr('id');
name = $(this.attr('name');
if (Number($(this).val()) === 0) {
if (name == 'static') {
do this
} else {
do this
}
} else {
do this
}
}
}
function onReadyHandler() {
$(".button-purple").click(chickHandler);
}
$(document).ready(onReadyHandler);
When you do something like .click(function(){...}), here function is called as a callback. You have to send a function as a callback. Not necessary to be anonymous.
I'm trying to create a function that adds an event to each button in a class. I have all of the buttons in an array and wanted to use Dustin Diaz's addevent() cross browser solution, but am unsure how to implement it. I'm used to using frameworks for this sort of thing, but have to use pure JS for this one.
Any pointers or advice on how to use Dustin's solution would be appreciated.
Ok so after taking #Pointy 's advice, I wrote this that checks for addEventListener and if not uses attachEvent This however is not calling testFunction(). What am I doing wrong here?
function addEvents()
{
var buttonArray=document.getElementsByClassName('mainButton');
for(i=0; i < buttonArray.length; i++)
{
if (i.addEventListener) {
i.addEventListener("click", testFunction);
}
else if (i.attachEvent) {
i.attachEvent("onclick", testFunction);
}
function testFunction() {
alert("Test");
}
}
// Attach an event to each button that when clicked on will display an alert that say 'Button X clicked' where X = the button ID
}
You are trying to add an event to a number. You should replace "i" with "buttonArray[i]" and add an else-case (defensive coding).
function addEvents() {
var buttonArray = document.getElementsByClassName('mainButton');
for(i = 0; i < buttonArray.length; i++) {
if (buttonArray[i].addEventListener) {
buttonArray[i].addEventListener("click", testFunction);
} else if (buttonArray[i].attachEvent) {
buttonArray[i].attachEvent("onclick", testFunction);
} else {
throw new Error("This should be unreachable");
}
}
function testFunction() {
alert("Test");
}
}
I've written a few events to handle opening and closing of a snap js drawer. This code below works, but I feel it could be written more efficiently. Any suggestions?
function openMobileMenu() {
event.preventDefault();
snapper.open('left');
$('#btn-menu').off('click', openMobileMenu);
$('#btn-menu').on('click', closeMobileMenu);
}
function closeMobileMenu() {
event.preventDefault();
snapper.close('left');
$('#btn-menu').on('click', openMobileMenu);
$('#btn-menu').off('click', closeMobileMenu);
}
$('#btn-menu').on('click', openMobileMenu);
Make your code modular and your concepts explicit.
You can start by creating a MobileMenu object which encapsulates the logic.
Note: The following code was not tested.
var MobileMenu = {
_snapper: null,
_$button: null,
_direction: 'left',
init: function (button, snapper, direction) {
this._$button = $(button);
this._snapper = snapper;
if (direction) this._direction = direction;
this._toggleSnapperVisibilityWhenButtonClicked();
},
_toggleSnapperVisibilityWhenbuttonClicked: function () {
this._$button.click($.proxy(this.toggle, this));
},
toggle: function () {
var snapperClosed = this._snapper.state().state == 'closed',
operation = snapperClosed? 'open' : 'closed';
this._snapper[operation](this._direction);
}
};
Then in your page you can just do the following to initialize your feature:
var mobileMenu = Object.create(MobileMenu).init('#btn-menu', snapper);
Modularizing your code will make it more maintainable and understandable in the long run, but also allow you to unit test it. You also gain a lot more flexibily because of the exposed API of your component which allows other code to interact with it.
E.g. you can now toggle the menu visibility with mobileMenu.toggle().
Use a variable to keep track of the state:
var menu_open = false;
$("#btn-menu").on('click', function(event) {
event.preventDefault();
if (menu_open) {
snapper.close('left');
} else {
snapper.open('left');
}
menu_open = !menu_open; // toggle variable
});
snap has a .state() method, which returns an object stuffed with properties, one of which is .state.
I think you want :
$('#btn-menu').on('click', function() {
if(snapper.state().state == "closed") {
snapper.open('left');
} else {
snapper.close('left');
}
});
Or, in one line :
$('#btn-menu').on('click', function() {
snapper[['close','open'][+(snapper.state().state == 'closed')]]('left');
});
Also, check How do I make a toggle button? in the documentation.