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@ArcticLight
Last active August 29, 2015 14:20
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CSS Animations + Javascript = Hell
// This is a snippet that may or may not eventually make it live to my wobsite.
// This is the shortest code I currently know how to write that triggers my
// in/out animations correctly on toggle - every time - in the browser.
// The "Every Time" bit is the hardest bit.
function toggleReq() {
requirementsOpen = !requirementsOpen;
if(requirementsOpen) {
req.style.height=document.getElementById("reqcontent").offsetHeight+8+"px";
//prevents animations from stepping on each others' toes.
if(sync !== null) { window.clearTimeout(sync); }
//Timeout required, because otherwise the browser will do Odd Things
//like flash a 0px tall height, or animate in from the wrong height.
sync = window.setTimeout(function() {
//frob whether or not we even want animations, because of the above
//"Browser will do bad things otherwise" reason.
req.classList.toggle("anim", true);
//finally make it small.
req.style.height="1em";
//==================
//CSS ANIMATIONS WHY
//==================
//Apparently all of this toggling is ENTIRELY NECESSARY,
//without which the animation will Not Always Start(tm)
document.getElementById("plus").classList.toggle("spinOut", true);
document.getElementById("hbar").classList.toggle("minus", true);
document.getElementById("hbar").classList.toggle("minus", false);
document.getElementById("plus").classList.toggle("spinIn", false);
sync = null;
}, 50);
} else {
//prevent toe-stepping-on
if(sync !== null) { window.clearTimeout(sync); }
//turn on animations
req.classList.toggle("anim", true);
//prep the spin animation
document.getElementById("plus").classList.toggle("spinOut", false);
document.getElementById("hbar").classList.toggle("minus", false);
//do the spin animation in a timeout, otherwise it (apparently) will
//not always frob correctly.
sync = window.setTimeout(function() {
document.getElementById("hbar").classList.toggle("minus", true);
document.getElementById("plus").classList.toggle("spinIn", true);
//In order to make the browser animate opening the div to the full
//content height, we must SPECIFY the full content height. Stating "auto"
//instead will cause the browser to animate the div to 0px and then suddenly
//snap to full height for who-knows-what-reason.
req.style.height=document.getElementById("reqcontent").offsetHeight+8+"px";
//in order to let the text reflow when the browser window is resized, we actually
//*DO* want the req-div's style to say height:auto. Unfortunately, as stated above,
//if we set it to auto it will animate like it has Palsy.
//The solution is yet ANOTHER setTimeout.
//
// "Let's Nest Even More Callbacks!" (dot-tumblr-dot-com)
sync = window.setTimeout(function() {
req.classList.toggle("anim", false);
req.style.height="auto";
sync = null;
}, 500);
}, 50);
}
}
@hawkw
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hawkw commented May 5, 2015

also, Is This Literate Programming? (yes)

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