Develop Reference

Jquery typing effect on scroll bug

Hi I have some js code that do typing effect on my web page it start typing when you scroll down end of page. For first it work normally but when you start scroll faster down to up the typing effect goes crazy how can I fix that
demo page
code
$(window).scroll(function (e) {
var elem = $(".hello-page");
var scrollTop = $(window).scrollTop();
var blockTop = elem.offset().top;
var docHeight = $(document).height();
var windowH = $(window).height();
if (scrollTop >= blockTop) {
var helloPageA = $(".hello-page").find("a");
var text = helloPageA.attr("data-text");
helloPageA.text('');
$.each(text.split(''), function (i, letter) {
setTimeout(function () {
helloPageA.html(helloPageA.html() + letter);
}, 150 * i);
});
} else {
elem.find("a").text('');
}
});
jsfiddle example
Thanks for your help

So, here is the solution - http://jsfiddle.net/u3ojjx8r/1/
I borrowed initial structure of the code from previous answer here and it was removed unfortunately, therefore I can't mention one of the co-authors. Though the code looked quite similar to topic-starter's one.
The idea of the code below is to separate the queuing of characters to render and the actual rendering. Another important improvement is always have control over timeouts, i.e. never schedule more than one timeout. That allows you to cancel them any time without unpredicted/uncontrolled behavior.
var timeoutVar;
var queue = [];
var drawQueueTimeout = -1;
var helloPageA = $(".hello-page").find("a");
function pushQueue (element) {
console.log('pushQUeue', element.char);
queue.push(element);
checkQueue();
}
function flushQueue () {
console.log('flushQueue');
queue = [];
clearTimeout(drawQueueTimeout);
drawQueueTimeout = -1;
}
function checkQueue () {
console.log('checkQueue', queue.length, drawQueueTimeout);
if (queue.length > 0 && drawQueueTimeout < 0) {
console.log('schedule drawQueue');
drawQueueTimeout = setTimeout(drawQueue, 150);
}
}
function drawQueue () {
drawQueueTimeout = -1;
console.log('draw queue');
if (queue.length > 0) {
var element = queue.shift();
console.log('drawQueue', element.char);
helloPageA.html(helloPageA.html() + element.char);
}
checkQueue();
}
$(window).scroll(function (e) {
var elem = $(".hello-page");
var scrollTop = $(window).scrollTop();
var blockTop = elem.offset().top;
var docHeight = $(document).height();
var windowH = $(window).height();
if (scrollTop + windowH == docHeight) {
// Empty anything typed so far
helloPageA.empty();
flushQueue();
var text = helloPageA.attr("data-text");
helloPageA.text('');
$.each(text.split(''), function (i, letter) {
pushQueue({
char: letter,
index: i
});
});
} else {
helloPageA.empty();
flushQueue();
}
});

Setting data type value to an element when it reaches the top of the viewport

I have a hex colour value stored on each section and when a section reaches the top of the screen (-180px for the header) I want to assign a css property to the header element in order to change the text colour as you scroll through the sections. I am not getting any errors and I am having trouble debugging this issue.
http://www.amypreston.co.uk/
$(window).load(function() {
var $header = $("header");
var numberOfSections = $("section").length;
var sectionOffsets = [];
var sectionColour = $("section").eq(i).data("colour");
for(var i = 0; i < numberOfSections; i++) {
sectionOffsets.push($("section").eq(i).offset().top);
}
$(window).scroll(function() {
var scrollTop = $(this).scrollTop();
for(var i = 0; i < numberOfSections; i++) {
if(scrollTop > sectionOffsets[i] - 180) {
$header.css('color', 'sectionColour');
}
}
});
});

I dont know if it happened by accident, but the line
var sectionColour = $("section").eq(i).data("colour");
is out of place. it uses a variable i which is only defined in the window scroll handler.
notice that you need to retrieve the section color each time the scroll handler runs, and not only on window load. you need to place this line from above in the loop inside the scroll handler.
Plus, as stated on the comments, you need to use the sectionColour as a variable, and not as a string like you do now. the single quote marks must be removed, so 'sectionColour' turns into sectionColour.
here is your fixed code:
$(window).load(function() {
var $header = $("header");
var numberOfSections = $("section").length;
var sectionOffsets = [];
for(var i = 0; i < numberOfSections; i++) {
sectionOffsets.push($("section").eq(i).offset().top);
}
$(window).scroll(function() {
var scrollTop = $(this).scrollTop();
for(var i = 0; i < numberOfSections; i++) {
if(scrollTop > sectionOffsets[i] - 180) {
var sectionColour = $("section").eq(i).data("colour");
$header.css('color', sectionColour);
}
}
});
});
On a side note, you could shorten your code into this:
$(window).scroll(function () {
$("section").each(function () {
if ($(window).scrollTop() > $(this).offset().top - 180) {
$("header").css('color', $(this).data("colour"));
}
});
}).scroll();

jQuery animation for each element

I do not have much experience in animation on Jquery. I want to make a simple animation that will highlight my text line by line with the possibility of stopping. I know how to do something like this for one line but I have no idea how to deal with loop.
here is my code:
var lines = $('#page')[0].getClientRects();
for (var i=0, max = lines.length; i < max; i++)
{
$('#under_liner')
.queue(function() {
$(this).css('top', lines[i].bottom).dequeue();
})
.animate({
width: lines[i].right - lines[i].left
}, 1000 )
.queue(function() {
$(this).css('width', 0).dequeue();
});
}
and jsfiddle http://jsfiddle.net/mz03kfua/2

I don't know if this is exactly what you are looking for, but here's how I'd do it.
Make a function that does the underlining
Make a recursive call on animation callback
Create a global variable to keep count of the current underlined line
Add a boolean that stops the function when false
var lines = $('#page')[0].getClientRects();
var play = true;
var index = 0;
underlineLine();
$('button').click(function(){
play = !play
if(play){
underlineLine()
$(this).html("STOP")
}else{
$(this).html("CONTINUE")
}
})
function underlineLine(){
if(index >= lines.length) return
if(play){
$('#under_liner').css('top', lines[index].bottom).dequeue();
$('#under_liner').css('width','0px');
$('#under_liner').animate({
width: lines[index].right - lines[index].left
}, 1000, function(){
underlineLine(index++)
})
$('#under_liner').css('width', 0).dequeue();
}
}
HERE IS A FIDDLE WITH THE CODE.
Hope it helps.

http://jsfiddle.net/mz03kfua/4/
var lines = $('#page')[0].getClientRects();
var current = 0;
var element;
function animateLine() {
if(typeof lines[current] !== "object") {
return;
}
var line = lines[current];
element = jQuery("<div />", {"class": "under_liner"}).prependTo("#page");
element.css({top: line.bottom}).animate({width: line.width}, 1000, function() {
current++;
animateLine();
});
}
function stopLine(e) {
e.preventDefault();
element.stop(true);
}
jQuery(".stop").click(stopLine);
animateLine();

DIV animation and color change

I'm trying to simulate TCP packet transmission, and hopefully I've made much progress. But now I want to fix two minor issues, that I need help with:
1- I want to highlight the corresponding cell in the table on the bottom of the page as yellow when the packet is being sent, and later when its ack is received, change the color to green.
2- The speed variable got from the input does not work!!
My code is here: http://jsfiddle.net/j26Qc/108/
$(document).ready(function () {
var count = 0;
var items = 0;
var packetNumber = 0;
var speed = 0;
var ssth= $("#ssth").val();
var window_left=0;
for(var i=1;i<=32;i++){
$('#table').append("<div class='inline' id='"+i+"'>"+i+"</div>");
}
document.getElementById(1).style.width=22;
$("button").click(function () {
if (count < ssth) {
if(items==0)
items=1;
else
items = items * 2;
count++;
} else {
items = items + 1;
}
window_left+=20;
window_width=items*20;
document.getElementById("window").style.left= window_left+"px";
document.getElementById("window").style.width=window_width+"px";
speed = $("#speed").val();
createDivs(items);
animateDivs();
});
function createDivs(divs) {
packetNumber = 1;
var left = 60;
for (var i = 0; i < divs; i++) {
var div = $("<div class='t'></div>");
div.appendTo(".packets");
$("<font class='span'>" + packetNumber + "</font>").appendTo(div);
packetNumber++;
div.css({
left: left
/* opacity: 0*/
}).fadeOut(0);
//div.hide();
//left += 20;
}
}
function animateDivs() {
$(".t").each(function (index) { // added the index parameter
var packet = $(this);
packet
.delay(index * 200)
.fadeIn(200)
.animate({left: '+=230px'}, speed)
.animate({left: '+=230px'}, speed)
.fadeOut(200, function () {
packet
.css({
top: '+=20px',
backgroundColor: "#f09090"
})
.text('a' + packet.text());
})
.delay(1000)
.fadeIn(200)
.animate({left:'-=230px'}, speed)
.animate({left:'-=230px'}, speed)
.fadeOut(200, function () {
packet
.css({
top: '-=20px',
backgroundColor: "#90f090"
});
});
}).promise().done(function(){
$(".packets").empty();});
}
});

1.
When it comes to coloring it is best to add an extra variable holding the count of items. A quick and dirty way, without adding a variable and instead using window_left / 20, would be in animateDivs():
// First fade
.fadeIn(200, function() {
$('#table #' + (index + window_left/20)).css({background:'yellow'});
})
// ...
// Second fade
.fadeIn(200, function() {
$('#table #' + (index + window_left/20)).css({background:'green'});
})
And in $("button").click(function () { right after first if{}else{}:
for (var i = 0 ; i < items + window_left / 20; ++i)
$('#table #' + (i)).css({background:'#fff'});
2.
When it comes to the speed you need to convert the value to int:
speed = parseInt($("#speed").val());
// Or
speed = +$("#speed").val();

Execute function IF another function is complete NOT when

I am having trouble creating a slider that pauses on hover, because I execute the animation function again on mouse off, if I flick the mouse over it rapidly (thereby calling the function multiple times) it starts to play up, I would like it so that the function is only called if the other function is complete, otherwise it does not call at all (to avoid queue build up and messy animations)
What's the easiest/best way to do this?
$(document).ready(function() {
//get variables
var slide_width = $('.slider_container').width();
var number_of_slides = $('.slider_container .slide').length;
var slider_width = slide_width*number_of_slides;
//set element dimensions
$('.slide').width(slide_width);
$('.slider').width(slider_width);
var n = 1;
$('.slider_container').hover(function() {
//Mouse on
n = 0;
$('.slider').stop(true, false);
}, function() {
//Mouse off
n = 1;
if (fnct == 0) sliderLoop();
});
//Called in Slide Loop
function animateSlider() {
$('.slider').delay(3000).animate({ marginLeft: -(slide_width * i) }, function() {
i++;
sliderLoop();
});
}
var i = 0;
var fnct = 0
//Called in Doc Load
function sliderLoop() {
fnct = 1
if(n == 1) {
if (i < number_of_slides) {
animateSlider();
}
else
{
i = 0;
sliderLoop();
}
}
fnct = 0
}
sliderLoop();
});
The slider works fine normally, but if I quickly move my mouse on and off it, then the slider starts jolting back and forth rapidly...been trying to come up with a solution for this for hours now..

Here's what fixed it, works a charm!
$(document).ready(function() {
//get variables
var slide_width = $('.slider_container').width();
var number_of_slides = $('.slider_container .slide').length;
var slider_width = slide_width*number_of_slides;
//set element dimensions
$('.slide').width(slide_width);
$('.slider').width(slider_width);
var n = 1;
var t = 0;
$('.slider_container').hover(function() {
clearInterval(t);
}, function() {
t = setInterval(sliderLoop,3000);
});
var marginSize = i = 1;
var fnctcmp = 0;
//Called in Doc Load
function sliderLoop() {
if (i < number_of_slides) {
marginSize = -(slide_width * i++);
}
else
{
marginSize = i = 1;
}
$('.slider').animate({ marginLeft: marginSize });
}
t = setInterval(sliderLoop,3000);
});