Force-DOM-reflow-JS

Overview and Install

Have you ever needed to force a dom reflow during transitions or other purposes? Do you find yourself frustrated with the cross browser solutions being too hackish and not-working-right? Then look no further. Simply insert the following 189-byte line of code into the top of your script to solve all your problems.

try{var forceReflowJS=(forceReflowJS=function(a){"use strict";void a.offsetHeight}).call.bind(Object.getOwnPropertyDescriptor(HTMLElement.prototype,"offsetHeight").get)}catch(e){}//anonyco

()

Then, the code above create a forceReflow function that gets passed an Element and reflows the element. Example usage.

try{var forceReflowJS=(forceReflowJS=function(a){"use strict";void a.offsetHeight}).call.bind(Object.getOwnPropertyDescriptor(HTMLElement.prototype,"offsetHeight").get)}catch(e){}//anonyco

forceReflowJS(document.documentElement); // reflows the whole page

Compatibility

The code is guarenteed to work in all current browsers and in IE 9 and up.

How It Works

You may have seen the following code snippets in production

var ele = document.getElementById("someRandomId");
ele.offsetHeight;

Or, some production snippets even go through the trouble of including a void to increase browser compatiblity.

var ele = document.getElementById("someRandomId");
void ele.offsetHeight;

However, lets face it: theese are hackish solutions that are flimsy and temporary because the browser can easily optimize the above statementes out. However, force-Reflow-JS is different in that it explictily tells the browser not to remove the statement through increasing the complexity of the statement to a degree at which one would not exert without reason and just cause. In English, when the browser sees forceReflowJS, it doesn't just see void ele.offsetHeight, rather it sees much more. Internally, the browser thinks like this when it sees forceReflowJS.

var ele = document.getElementById("someRandomId");
ele["offsetHeight"] /*%<-- VERY IMPORTANT CODE SNIPPET! DO NOT REMOVE! URGENT! THIS IS THE BROWSER SPEAKING TO ITSELF! -->%*/;

Please note that while the alternatives are flimsy, ForceReflowJS unfourtunately has to fall back to void ele.offsetHeight in unsupporting browsers. However, no need to worry too much: these unsupporting browsers likely do not optimize enough to be able to get rid of this flmsy statement.