You don't need a plugin for this. This works on textareas of any size, height or row size and will only work when the contents exceeds the textarea. Firstly set the overflow on your target textareas to hidden and resize to none, then add the following functionality to the textareas you want to autogrow. Not only will it increase the textarea's size as the user types, it'll also auto-shrink it when they delete stuff.
$('textarea').on('paste input', function () {
if ($(this).outerHeight() > this.scrollHeight){
$(this).height(1)
}
while ($(this).outerHeight() < this.scrollHeight + parseFloat($(this).css("borderTopWidth")) + parseFloat($(this).css("borderBottomWidth"))){
$(this).height($(this).height() + 1)
}
});
It works by measuring if the scroll height of the textarea is bigger than the outer height, which it only will be if there's more text than the textarea can hold - and it takes border size into account for higher accuracy. Using paste and input means it will only increase when the user physically changes the value of the textarea, as opposed to when they press any key. It's petty but a textarea shouldn't grow when somebody presses an arrow key or something.
It might be prudent to add a No JS option that re-enables overflow and resizing for those who don't have Javascript, else they'll be stuck with a tiny box.
