Develop Reference

Make a Testimonial Scroller Stay on the Screen Before Fading Out

I have a testimonial scroller that shows one testimonial, fades out, shows the next, fades out, and returns to the first.
My issue is that after the fade in animation, the fade out animation begins immediately. It doesn't give enough time for someone to read it.
$(document).ready(function() {
function doFade() {
$("#one").fadeIn(6000,function() {
$("#one").fadeOut(6000).delay(3000);
setTimeout(fadeTwo,6000);
});
}
function fadeTwo() {
$("#two").fadeIn(6000,function() {
$("#two").fadeOut(6000).delay(3000);
setTimeout(fadeThree,6000);
});
}
function fadeThree() {
$("#three").fadeIn(4000,function() {
$("#three").fadeOut(6000).delay(3000);
setTimeout(doFade,6000);
});
}
doFade();
});

jQuery's delay function will only delay functions that are called after it in the chain, so it is having no effect on your code. Delay docs
You need to use it before the call to fadeOut, e.g.
$(document).ready(function() {
function doFade() {
$("#one").fadeIn(6000,function() {
setTimeout(fadeTwo,6000);
})
.delay(3000)
.fadeOut(6000);
}
function fadeTwo() {
$("#two").fadeIn(6000,function() {
setTimeout(fadeThree,6000);
})
.delay(3000)
.fadeOut(6000);
}
function fadeThree() {
$("#three").fadeIn(6000,function() {
setTimeout(doFade,6000);
})
.delay(3000)
.fadeOut(6000);
}
doFade();
});
Edit:
You are currently setting a timeout to execute the next function, within the complete callback of fadeIn. This is a bit confusing to my mind, and I think it is simpler and clearer to do something like the following. In addition, there is no reason to define the three functions within the ready function - it is personal preference but I like to keep the amount of code within a callback to a minimum, such as...
$(document).ready(function() {
doFade();
});
function doFade() {
setTimeout(fadeTwo,12000);
$("#one").fadeIn(6000).delay(3000).fadeOut(6000);
}
function fadeTwo() {
setTimeout(fadeThree,12000);
$("#two").fadeIn(6000).delay(3000).fadeOut(6000);
}
function fadeThree() {
setTimeout(doFade,12000);
$("#three").fadeIn(6000).delay(3000).fadeOut(6000);
}
Edit 2:
In further effort to reduce the amount we repeat ourselves, we can extract the whole animation sequence into a function:
$(document).ready(function() {
doFade();
});
function fadeInThenOut(element) {
element.fadeIn(6000).delay(3000).fadeOut(6000);
}
function doFade() {
setTimeout(fadeTwo,12000);
fadeInThenOut($("#one"));
}
function fadeTwo() {
setTimeout(fadeThree,12000);
fadeInThenOut($("#two"));
}
function fadeThree() {
setTimeout(doFade,12000);
fadeInThenOut($("#three"));
}
Edit 3:
At this point we probably notice how similar our three functions are, and want some way to reduce that repetitiveness. So we could use recursion, and just change which element we pass in each time.
$(document).ready(function() {
doFade();
});
function doFade(elementNumber) {
const elementNumber = elementNumber < testimonialElements.length ? elementNumber : 0;
setTimeout(doFade(elementNumber + 1),12000);
$('#' + testimonialElements[elementNumber]).fadeIn(6000).delay(3000).fadeOut(6000);
}
var testimonialElements = ["one","two","three"];
While this solution may lose something in readability and simplicity, the great advantage is that when you add a fourth testimonial, you don't need to write a function to handle it. All you would do is change the testimonialElements array to include the new element id.

jQuery AUTOMATIC scroll (no button click) on document ready

I am creating a chat, everything works perfectly, it scrolls down when i click the "Send" button, but I want it to scroll all the way down when the document is ready. I have done this by adding the scrolling function to setInterval, but the problem with that is that the user basically cant scroll up to see previous chat messages because he gets scrolled down every 0.1 seconds. My code is:
$(function () {
//$("#messages").scrollTop($("#messages").prop("scrollHeight")); Doesnt work at all
function updateChat(){
$("#messages").load('chat/ajaxLoad.php');
//$("#messages").scrollTop($("#messages").prop("scrollHeight")); This works but the user cannot scroll up anymore
}
setInterval(function () {
updateChat();
}, 100);
$("#post").submit(function(){
$.post("chat/ajaxPost.php", $('#post').serialize(), function (data) {
$("#messages").append('<div>'+data+'</div>');
$("#messages").scrollTop($("#messages").prop("scrollHeight")); // This works but only when the user presses the send button
$("#text").val("");
});
return false;
});
});

Add this to your code.
var chat = $("#messages").html();
setInterval(function () {
updateChat();
if(chat !== $("#messages").html()){
$("#messages").scrollTop($("#messages").prop("scrollHeight"));
chat = $("#messages").html();
}
}, 2000);
I think this should work (didnt test), but there are some better ways you can optimise this like not saving the whole .html() into a variable.
The idea here is that it checks if the content is changed every 2 seconds. If it is, it scrolls down.

I see what's your problem and I have 2 ideas for you :
You scroll down only when a new message is post, for example with an Ajax request you could check if number of messages is > in compare with the last 0.1s, if yes you scroll if not you ignore.
You scroll down every 1-2s only if the scroll is at the maximum bottom position. If the scroll is not at the maximum you do not scroll. I feel this solution is better.

You need to seperate the actions on your application,
also you missed many checks that can make the application work properly and will
make it easy to maintain.
How i suggestion the code will look:
$(function () {
function updateMessages(){
var messages_before_update = $("#messages").html();
$("#messages").load('chat/ajaxLoad.php');
var message_after_update = $("#messages").html();
if(messages_before_update !== message_after_update){
scrollToBottom();
}
}
function scrollToBottom(){
var scroll_height = $("#messages").prop("scrollHeight");
var scroll_top = $("#messages").scrollTop();
if(scroll_height !== scroll_top){
$("#messages").scrollTop($("#messages").prop("scrollHeight"));
}
}
function addMessage(message){
$("#messages").append('<div>' + message + '</div>');
}
setInterval(updateMessages, 100);
$("#post").submit(function () {
$.post("chat/ajaxPost.php", $('#post').serialize(), function (data) {
addMessage(data);
scrollToBottom();
$("#text").val("");
});
return false;
});
});

Attaching contextMenu to flot graph points

I am trying to attach the jQuery plugin contextMenu to the points in a flot graph. I have the right click context menu working using the following code:
$(".chart").bind("plotclick").contextMenu('myMenu1', {
bindings: {
'delete': function(t) {
// Do stuff when delete is clicked
}
}
});
With the above, if I right click on any of the points on the graph a little menu pops up with "DELETE" in it.
However I need access to the data provided by flot about the point that was clicked. Normally the plotclick function would look like this:
$(".chart").bind("plotclick", function (event, pos, item) {
// In here I can see details about the point that was clicked by looking at event, pos and item
})
So my question is, how do I pass the event, pos, item variables through to the delete function of the contextMenu in my first code above? Is what I'm doing even the right way to attach the contextMenu?
Thanks

How about your bind the context menu generically to the plot container div and then use the plothover event to keep track of whether or not you are "over" a point? If you aren't over a point, you suppress the pop-up, if you are over one you get the point information from a global-scoped variable.
$("#placeholder").contextMenu('myMenu1', {
onContextMenu: function(e) {
if (somePoint) return true;
else return false;
},
bindings: {
'delete': function(t) {
alert(lastPoint.series.label);
}
}
});
var somePoint = null, lastPoint = null;
$("#placeholder").bind("plothover", function (event, pos, item) {
if (item){
somePoint = item;
}else{
lastPoint = somePoint;
somePoint = null;
}
});
Fiddle here.
BTW, the reason my original fiddle didn't work, was I had the wrong jquery context menu. I thought you were using this one not this one.

Adding a Quiz Timer, Fade Out/Skip to the next if timer reaches 0

I'm really new to jQuery but familiar with some other languages. I recently bought a quiz type script and I'm trying to add a simple 15 second timer to each question. It's only a fun quiz, so no need to worry about users playing with the javascript to increase time etc.
Basically, if a user does not pick a question within 15 seconds, it will automatically go on to the next question and the timer starts over again.
Answers have the .next tag, and when chosen it moves onto the next question as the code below shows (hopefully).
superContainer.find('.next').click(function () {
$(this).parents('.slide-container').fadeOut(500, function () {
$(this).next().fadeIn(500)
});
return false
});
The problem i have is if i use setInterval, i don't know how i can select the appropriate div again for fade it our and fade in the next one. I've tried the below code and a few similar scrappy idea's but it doesn't work, but maybe it will give a better idea of what I'm after though.
superContainer.find('.next').click(function () {
$active_count = $count;
countInterval = setInterval(function() {
$active_count--;
if($active_count <= 0){
clearInterval(countInterval);
$active_count = $count;
$(this).parents('.slide-container').fadeOut(500, function () {
$(this).next().fadeIn(500)
});
}
$('.question-timer').html($active_count);
}, 1000);
$(this).parents('.slide-container').fadeOut(500, function () {
$(this).next().fadeIn(500)
});
return false
});
I've only been using JQuery a day or two so excuse any obvious mistakes and bad code! Let me know if you need any other code or information

This is moderately tricky for a first jQuery project.
The knack (in this solution) is to factor out a goNext function that can be called in two ways - in response to a click event and in response to a 15 second setTimeout(), not setInterval().
$(function(){
var questionTimeout = null;
function goNext($el) {
clearTimeout(questionTimeout);
var $next = $el.next();
$el.fadeOut(500, function() {
if($next.length > 0) {
$next.fadeIn(500, function() {
questionTimeout = setTimeout(function() {
goNext($next);
}, 15000);
});
}
else {
afterLastQuestion();
}
});
}
function afterLastQuestion(){
alert("last question complete");
$start.show();
}
var $superContainer = $("#superContainer").on('click', '.next', function() {
goNext($(this).closest('.slide-container'));
return false;
});
var $start = $("#start").on('click', function(){
$(this).hide();
$superContainer.find(".slide-container")
.eq(0).clone(true,true)
.prependTo(superContainer)
.find(".next").trigger('click');
return false;
});
});
DEMO
The process is started by clicking a "start" link, causing the first question to be cloned followed by a simulated click on the clone's "next" link. This ensures that the (actual) first question is treated in exactly the same way as all the others.
I also included a afterLastQuestion() function. Modify its action to do whatever is necessary after the last question is answered (or times out).

You could keep the current question in a variable, resetting it on a next click and in the timer, e.g.
var $current;
superContainer.find('.next').click(function (e) {
e.preventDefault();
$(this).parents('.slide-container').fadeOut(500, function () {
$(this).next().fadeIn(500);
$current = $(this).next();
});
});​
You'll just need to set it to your first question on initialisation, and remember to reset your timer on a next click
Also, it's usually preferable to use e.preventDefault() rather than return false.

Using multiple instances of setInterval

I have a jsFiddle here: http://jsfiddle.net/dztGA/22/
The goal: Essentially, I'm trying to have 2 discrete timers on the same page that can be destroyed and re-created on mouseover/mouseout (pause), or on manual progression (restart).
The problem: What my jsFiddle's single timer will illustrate is that when I click "Stop Timer", my setInterval (stored in variable t) seems to have multiple instances albeit being destroyed with clearInterval(t). This becomes apparent when I click "Restart Timer" and it seems to have 2+ independent timers as illustrated by the quick increment.
A caveat: I have done as much research on SO as I can, but because I'll be having 2 different sliders on the page, I can't use any "clear all timers" methods, so I tried storing each in a variable.
I hope that's clear. Thanks for the view.

To fix your current issue: Add clearInterval(window.t) at the onclick function of the reset button.
A method to be able to have multiple timers. This requires a certain structure, though.
Fiddle (6 timers!): http://jsfiddle.net/dztGA/27/
(function(){ //Anonymous function, to not leak variables to the global scope
var defaultSpeed = 3000; //Used when missing
var timerSpeed = [500, 1000, 2000, 4000, 8000];
var intervals = [];
function increase(i){
return function(){
var elem = $("#count"+i);
elem.text(parseFloat(elem.text()) + 1);
}
}
function clear(i){
return function(){
clearInterval(intervals[i]);
}
}
function restart(i){ //Start AND restart
return function(){
clear(i)();
increase(i)();
intervals[i] = setInterval(increase(i), timerSpeed[i]||defaultSpeed);
}
}
// Manual increment
$('input[name=increment]').each(function(i){
$(this).click(function(){
restart(i)();
increase(i)();
});
});
// Clear timer on "Clear"
$('input[name=clear]').each(function(i) {
$(this).click(clear(i));
});
// Restart timer on "Restart"
$('input[name=reset]').each(function(i) {
$(this).click(restart(i));
//Optionally, activate each timer:
increase(i)();
});
})();

// Clear timer on "Clear"
$('input[name=clear]').click(function() {
window.clearInterval(t);
});
should be
// Clear timer on "Clear"
$('input[name=clear]').click(function() {
window.clearInterval(window.t);
});
because this is the input not Window