javascript - WOW.js start animation when element is 60% in screen -

using wow.js, possible start animation when x% of element visible rather using offset value?

for example have element width , height of 300px, , if set x% 50% animation start when user has scrolled enough 150px of element on screen.

i looked on source code of wow.js , doesn't there's way specify offset percentage rather in pixels. here's how in javascript:

window.onload = function() {     var elements = document.getelementsbyclassname("offsetme50");     var i;     (i = 0; < elements.length; i++) {         var offset = elements[i].clientheight * .5;   //.5 = 50%         elements[i].setattribute("data-wow-offset", offset);     } } 

this code run automatically after page loaded. set class="offsetme50" html elements want.