change css class property increment - javascript

I have a small question!
I'am trying to change css width property using JavaScript like this:
document.getElementById("progressvalue").style.width = "80%";
.progress {
width: 100%;
max-width: 500px;
border: 3px solid black;
height: 20px;
padding: 1px;
}
#progressvalue {
height: 100%;
width: 0%;
background-color: #05e35e;
}
<div class="progress">
<div id="progressvalue"></div>
</div>
But instead of 80% in JavaScript code, I want to increase the width value by 20%.
Like (width = width + 20%)
I want to apply this changing once (So I can use it mutiple times using other conditions), and this is why I need it like this (width = width + 20%)

You can try to read the element's style.width property, by keeping only the numeric part of it and adding it to your step (eg 20%).
const step = 5;
const updateProgress = () => {
const currentWidth = Number(document.getElementById("progressvalue").style.width.replace( "%", ""));
if (currentWidth>=100) {
return;
}
else {
document.getElementById("progressvalue").style.width = `${currentWidth+step}%`;
}
}
You can check this out in this CodePen.

I guess you want to do some animation right ? If so you can use recursivity with setTimeout:
function progress(val) {
val += 20;
document.getElementById("progressvalue").style.width = val + "%";
if (val < 100) // To stop the loop when progress bar is full
setTimeout(function () {
progress(val);
}, 1000)
}
progress(0); // Start the animation

This will increase by 20% every 0.5 seconds.
let percent = 0;
setInterval(() =>
{
if(percent > 100) {
clearInterval();
return;
}
document.getElementById("progressvalue").style.width = percent + "%";
percent += 20;
}, 500);

You can use this:
var el = document.getElementById("progressvalue");
var elementWidth = el.style.width;
var newWidth = `${20+parseInt(elementWidth.substring(0, elementWidth.length-1))}%`
el.style.width=newWidth;
Assuming that you have set the width of the element initially to a percent value.

<button type="button" id="myBtn" onclick="myFunction()">Change the width</button>
<script>
function myFunction() {
let progress = document.getElementById("progressvalue");
let style = window.getComputedStyle(progress, null).getPropertyValue('width');
let currentSize = parseFloat(style);
progress.style.width = (currentSize + 20) + '%';
}
</script>

You can try it
//offsetWidth : returns the width of the element
var element_width=document.getElementById("progressvalue").offsetWidth
document.getElementById("progressvalue").style.width =element_width + (20*element_width/100) +'px' ;

You need to get the current width of <div id="progressvalue"></div>, put it in a variable and add 20 and reassign that value to <div id="progressvalue"></div>.

Related

progress bar increases as we press the button

I am new to programming but trying to solve a problem.
I am trying to increase a progress bar as I press on the "d" button. I am trying to do it recursively but I don't have enough skills to do it properly. Any help would be greately appreciated.
My js file looks like this so far:
window.addEventListener('keypress', function(e) {
function counter(p) {
//if the button is "d"
if (e.keyCode === 100) {
//target progressbar width and increase it
$('#progressbar').css('width', function(index, value) {
return $("#progressbar").css('width', ((p * 2) + "%"));
});
if ($('#progressbar').width() < 100) {
return counti(p + 1)
}
}
};
counti(1);
});
My html:
<div id = "myProgress" >
<div id = "progressbar" > 0 / 50 </div>
</div>
var count = 0;
var maxCount = 50;
var progressBar = document.getElementById("progressbar")
window.addEventListener("keypress", function(e) {
//if the button is "d"
if (e.keyCode === 100) {
// increase count if it's less than maxCount
count = count === maxCount ? maxCount : count + 1;
//target progressbar width and increase it
var newWidth = (count / maxCount) * 100 + "%";
progressBar.style.width = newWidth;
progressBar.innerHTML = count + "/" + maxCount
}
});
#myProgress {
width: 400px;
height: 30px;
background-color: #e4e4e4;
}
#progressbar {
width: 0%;
height: 30px;
background-color: #5980a7;
color: #fff;
}
<div id="myProgress">
<div id="progressbar">0/50</div>
</div>

How can I use requestAnimationFrame along with setInterval?

See the following snippet of code.
It creates a loader on click of a button. But the animation is not smooth.
I have recently read about requestAnimationFrame function which can do this job. But how can I use it to replace setInterval altogether since there is no way to specify time in requestAnimationFrame function.
Can it be used in conjunction with setInterval ?
let idx = 1;
const timetoEnd = 5000;
function ProgressBar(width){
this.width = width || 0;
this.id = `pBar-${idx++}`;
this.create = () => {
let pBar = document.createElement('div');
pBar.id = this.id;
pBar.className = `p-bar`;
pBar.innerHTML = `<div class="loader"></div>`;
return pBar;
};
this.animator = () => {
let element = document.querySelector(`#${(this.id)} div`);
if(this.width < 100){
this.width++;
element.style.width = `${this.width}%`;
} else {
clearInterval(this.interval);
}
};
this.animate = () => {
this.interval = setInterval(this.animator, timetoEnd/100);
}
}
function addLoader (){
let bar1 = new ProgressBar(40);
let container = document.querySelector("#container");
container.appendChild(bar1.create());
bar1.animate();
}
.p-bar{
width: 400px;
height: 20px;
background: 1px solid #ccc;
margin: 10px;
overflow:hidden;
border-radius: 4px;
}
.p-bar .loader{
width: 0;
background: #1565C0;
height: 100%;
}
<input type="button" value="Add loader" onclick="addLoader()" />
<div id="container"></div>
You are right, requestAnimationFrame is the recommended way to avoid UI jam when doing animation.
You can remember the absolute starting time at start instead of trying to do this at each frame. Then it's just a matter of computing a width based on the delta time between start and current time.
Also, document.querySelector is considered a relatively "heavy" operation so I added this.element to avoid doing it at each frame.
Here is how to new width is computed: ((100 - this.startWidth) / timetoEnd) * deltaT + this.startWidth
100 - this.startWidth is the total amount of width we have to animate
(100 - this.startWidth) / timetoEnd is how much width each second must add to (1)
((100 - this.startWidth) / timetoEnd) * deltaT is how much width we have to add to (1)
We just have to shift the whole thing this.startWidth px to have the frame's width
Also notice that some of this computation is constant and do not have to be computed on each frame, which I left as an exercise :)
Here is your slightly adapted code:
let idx = 1;
const timetoEnd = 5000;
function ProgressBar(startWidth){
this.startWidth = startWidth || 0;
this.id = `pBar-${idx++}`;
this.create = () => {
let pBar = document.createElement('div');
pBar.id = this.id;
pBar.className = `p-bar`;
pBar.innerHTML = `<div class="loader"></div>`;
return pBar;
};
this.animator = () => {
const deltaT = Math.min(new Date().getTime() - this.start, timetoEnd);
if(deltaT < timetoEnd){
const width = ((100 - this.startWidth) / timetoEnd) * deltaT + this.startWidth;
this.element.style.width = `${width}%`;
requestAnimationFrame(this.animator.bind(this))
}
};
this.animate = () => {
this.element = document.querySelector(`#${(this.id)} div`);
this.start = new Date().getTime();
this.animator();
}
}
function addLoader (){
let bar1 = new ProgressBar(40);
let container = document.querySelector("#container");
container.appendChild(bar1.create());
bar1.animate();
}
.p-bar{
width: 400px;
height: 20px;
background: 1px solid #ccc;
margin: 10px;
overflow:hidden;
border-radius: 4px;
}
.p-bar .loader{
width: 0;
background: #1565C0;
height: 100%;
}
<input type="button" value="Add loader" onclick="addLoader()" />
<div id="container"></div>

Jump/scroll to #id within a scroll element [duplicate]

I have a div that has overflow: scroll and I have some elements inside the DIV that are hidden. On click of a button on the page, I want to make the DIV scroll to a particular element inside the DIV.
How do I achieve this?
You need to read the offsetTop property of the div you need to scroll to and then set that offset to the scrollTop property of the container div. Bind this function the event you want to :
function scrollToElementD(){
var topPos = document.getElementById('inner-element').offsetTop;
document.getElementById('container').scrollTop = topPos-10;
}
div {
height: 200px;
width: 100px;
border: 1px solid black;
overflow: auto;
}
p {
height: 80px;
background: blue;
}
#inner-element {
background: red;
}
<div id="container"><p>A</p><p>B</p><p>C</p><p id="inner-element">D</p><p>E</p><p>F</p></div>
<button onclick="scrollToElementD()">SCROLL TO D</button>
function scrollToElementD(){
var topPos = document.getElementById('inner-element').offsetTop;
document.getElementById('container').scrollTop = topPos-10;
}
Fiddle : http://jsfiddle.net/p3kar5bb/322/ (courtesy #rofrischmann)
Just improved it by setting a smooth auto scrolling inside a list contained in a div
https://codepen.io/rebosante/pen/eENYBv
var topPos = elem.offsetTop
document.getElementById('mybutton').onclick = function () {
console.log('click')
scrollTo(document.getElementById('container'), topPos-10, 600);
}
function scrollTo(element, to, duration) {
var start = element.scrollTop,
change = to - start,
currentTime = 0,
increment = 20;
var animateScroll = function(){
currentTime += increment;
var val = Math.easeInOutQuad(currentTime, start, change, duration);
element.scrollTop = val;
if(currentTime < duration) {
setTimeout(animateScroll, increment);
}
};
animateScroll();
}
//t = current time
//b = start value
//c = change in value
//d = duration
Math.easeInOutQuad = function (t, b, c, d) {
t /= d/2;
if (t < 1) return c/2*t*t + b;
t--;
return -c/2 * (t*(t-2) - 1) + b;
};
I guess it may help someone :)
Here's a simple pure JavaScript solution that works for a target Number (value for scrollTop), target DOM element, or some special String cases:
/**
* target - target to scroll to (DOM element, scrollTop Number, 'top', or 'bottom'
* containerEl - DOM element for the container with scrollbars
*/
var scrollToTarget = function(target, containerEl) {
// Moved up here for readability:
var isElement = target && target.nodeType === 1,
isNumber = Object.prototype.toString.call(target) === '[object Number]';
if (isElement) {
containerEl.scrollTop = target.offsetTop;
} else if (isNumber) {
containerEl.scrollTop = target;
} else if (target === 'bottom') {
containerEl.scrollTop = containerEl.scrollHeight - containerEl.offsetHeight;
} else if (target === 'top') {
containerEl.scrollTop = 0;
}
};
And here are some examples of usage:
// Scroll to the top
var scrollableDiv = document.getElementById('scrollable_div');
scrollToTarget('top', scrollableDiv);
or
// Scroll to 200px from the top
var scrollableDiv = document.getElementById('scrollable_div');
scrollToTarget(200, scrollableDiv);
or
// Scroll to targetElement
var scrollableDiv = document.getElementById('scrollable_div');
var targetElement= document.getElementById('target_element');
scrollToTarget(targetElement, scrollableDiv);
You need a ref to the div you wish to scroll to inner-div and a ref to the scrollable div scrollable-div:
const scrollToDiv = () => {
const innerDivPos = document.getElementById('inner-div').offsetTop
document
.getElementById('scrollable-div')
.scrollTo({ top: innerDivPos, behavior: 'smooth' })
}
<div id="scrollable-div" style="height:100px; overflow-y:auto;">
<button type="button" style="margin-bottom:500px" onclick="scrollToDiv()">Scroll To Div</button>
<div id="inner-div">Inner Div</div>
</div>

Draggable Columns With Pure JavaScript

I'm trying to build a draggable column based layout in JavaScript and having a bit of hard time with it.
The layout comprises of 3 columns (divs), with two dragable divs splitting each. The idea is that they are positioned absolutely and as you drag the draggers, the columns' respective widths, and left values are updated.
The three columns should always span the full width of the browser (the right most column is 100% width), but the other two should remain static by default when the browser is resized (which is why i'm using px, not %).
My code isn't working as of yet, I'm relatively new to JavaScript (which is why I don't want to use jQuery).
Having said that, there must be a more efficient (and cleaner) way of achieving this with less code that works (without reaching for the $ key).
If anyone with some awesome JS skills can help me out on this I'd be super-appreciative.
Here's the fiddle I'm working on http://jsfiddle.net/ZFwz5/3/
And here's the code:
HTML
<!-- colums -->
<div class="col colA"></div>
<div class="col colB"></div>
<div class="col colC"></div>
<!-- draggers -->
<div class="drag dragA" style="position: absolute; width: 0px; height: 100%; cursor: col-resize; left:100px;"><div></div></div>
<div class="drag dragB" style="position: absolute; width: 0px; height: 100%; cursor: col-resize; left: 300px;"><div></div></div>
CSS:
body {
overflow:hidden;
}
.col {
position: absolute;
height:100%;
left: 0;
top: 0;
overflow: hidden;
}
.colA {background:red;width:100px;}
.colB {background:green; width:200px; left:100px;}
.colC {background:blue; width:100%; left:300px;}
.drag > div {
background: 0 0;
position: absolute;
width: 10px;
height: 100%;
cursor: col-resize;
left: -5px;
}
and my terrible JavaScript:
//variabe columns
var colA = document.querySelector('.colA');
var colB = document.querySelector('.colB');
var colC = document.querySelector('.colC');
//variable draggers
var draggers = document.querySelectorAll('.drag');
var dragA = document.querySelector(".dragA");
var dragB = document.querySelector(".dragB");
var dragging = false;
function drag() {
var dragLoop;
var t = this;
var max;
var min;
if (dragging = true) {
if (this == dragA) {
min = 0;
max = dragB.style.left;
} else {
min = dragA.style.left;
max = window.innerWidth;
}
dragLoop = setInterval(function () {
var mouseX = event.clientX;
var mouseY = event.clientY;
if (mouseX >= max) {
mouseX = max;
}
if (mouseY <= min) {
mouseY = min;
}
t.style.left = mouseX;
updateLayout();
}, 200);
}
}
function updateLayout() {
var posA = dragA.style.left;
var posB = dragB.style.left;
colB.style.paddingRight = 0;
colA.style.width = posA;
colB.style.left = posA;
colB.style.width = posB - posA;
colC.style.left = posB;
colC.style.width = window.innerWidth - posB;
}
for (var i = 0; i < draggers.length; i++) {
draggers[i].addEventListener('mousedown', function () {
dragging = true;
});
draggers[i].addEventListener('mouseup', function () {
clearInterval(dragLoop);
dragging = false;
});
draggers[i].addEventListener('mouseMove', function () {
updateLayout();
drag();
});
}
I see a couple of things wrong here. First of all, the mousemove event only fires on an element when the mouse is over that element. You might have better luck registering a mousemove listener on the parent of your div.drag elements, then calculating the mouse's position inside that parent whenever a mouse event happens, then using that position to resize your columns and your draggers.
Second, I'm not quite sure what you're trying to do by registering a function with setInterval. You're doing pretty well with registering event listeners; why not continue to use them to change the state of your DOM? Why switch to a polling-based mechanism? (and the function you pass to setInterval won't work anyway - it refers to a variable named event, which in that context is undefined.)
This is just a little example... I hope it can help you :)
window.onload = function() {
var myDiv = document.getElementById('myDiv');
function show_coords(){
var monitor = document.getElementById('monitor');
var x = event.clientX - myDiv.clientWidth / 2;
var y = event.clientY - myDiv.clientWidth / 2;
monitor.innerText = "X: " + x + "\n" + "Y: " + y;
myDiv.style.left = x + "px";
myDiv.style.top = y + "px";
}
document.onmousemove = function(){
if(myDiv.innerText == "YES"){show_coords();}
}
myDiv.onmousedown = function(){
myDiv.innerText = "YES";
}
myDiv.onmouseup = function(){
myDiv.innerText = "NO";
}
}

JavaScript Div Expanding

I hope someone can help me with this.
When my HTML Textbox is clicked, I would like a Div to expand in length using preferably only JavaScript. I attached a picture to show in more depth. Again, If anyone could help me - I'll be greatfull.
Something like this should be sufficient, HTML:
<input type = "text" style = "width: 500px;" onfocus = "expand();" onblur = "collapse();">
<div id = "yourdiv"></div>
CSS:
#yourdiv {
margin-top: 0px;
background-color: rgb(0, 162, 232);
width: 500px;
height: 0px;
}
JavaScript:
var t;
function expand() {
var dv = document.getElementById("yourdiv");
var duration = 500; //number of milliseconds for animation; 1000ms = 1s.
var stepDur = Math.floor(duration / 200); //200px is our goal height here
var curHeight = parseInt(dv.style.height.substr(0, dv.style.height.length - 2), 10); //current height of dv
if(isNaN(curHeight)) {
curHeight = 0;
}
clearTimeout(t); //make sure no other animation is happening
function doAnim() {
if(curHeight >= 200) {
//we're done!
return;
}
curHeight ++;
dv.style.height = curHeight + "px";
t = setTimeout(doAnim, stepDur);
}
doAnim();
}
function collapse() {
var dv = document.getElementById("yourdiv");
var duration = 500; //number of milliseconds for animation; 1000ms = 1s.
var stepDur = Math.floor(duration / 200);
var curHeight = parseInt(dv.style.height.substr(0, dv.style.height.length - 2), 10); //current height of dv
clearTimeout(t); //make sure no other animation is happening
function doAnim() {
if(curHeight <= 0) {
//we're done!
return;
}
curHeight --;
dv.style.height = curHeight + "px";
t = setTimeout(doAnim, stepDur);
}
doAnim();
}
Demo: little link.
I hope that helped!

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