传统的表单控件textarea元素中用cols和rows来规定textarea的尺寸的示例是什么？

<form action="#">
    cols:<input id="cols" pattern="\d" placeholder="请输入0-9的数字"><br>
    rows:<input id="rows" pattern="\d" placeholder="请输入0-9的数字">
    <input id="set" type="submit" value="设置">    
    <textarea id="test"></textarea>        
</form>

<script>
var cols = document.getElementById('cols');
var rows = document.getElementById('rows');
var test = document.getElementById('test');
var set = document.getElementById('set');
set.onclick = function(){
    test.setAttribute('cols',cols.value);
    test.setAttribute('rows',rows.value);
};
</script>