You can't animate to or from a dimension of "auto" (unfortunately). My usual approach for this is to animate the height of an outer DIV which has a single child which is a style-less DIV used only for measuring the content height.
function growDiv() {
var growDiv = document.getElementById('grow');
if (growDiv.clientHeight) {
growDiv.style.height = 0;
} else {
var wrapper = document.querySelector('.measuringWrapper');
growDiv.style.height = wrapper.clientHeight + "px";
}
}
#grow {
-moz-transition: height .5s;
-ms-transition: height .5s;
-o-transition: height .5s;
-webkit-transition: height .5s;
transition: height .5s;
height: 0;
overflow: hidden;
outline: 1px solid red;
}
The contents of my div.
The contents of my div.
The contents of my div.
The contents of my div.
The contents of my div.
The contents of my div.
