简单的 jQuery 解决方案是：
$(function() {
$('textarea').each(function() {
$(this).height($(this).prop('scrollHeight'));
});
});
Check Fiddle. http://jsfiddle.net/ZurAk/291/
由于您需要一个简单的 JavaScript 解决方案，请使用以下创建的脚本用户潘子 https://stackoverflow.com/users/277767/panzi。你可以查看原答案here https://stackoverflow.com/a/5346855/1762224.
var observe;
if (window.attachEvent) {
observe = function (element, event, handler) {
element.attachEvent('on'+event, handler);
};
}
else {
observe = function (element, event, handler) {
element.addEventListener(event, handler, false);
};
}
function init () {
var text = document.getElementById('textarea');
function resize () {
text.style.height = 'auto';
text.style.height = text.scrollHeight+'px';
}
/* 0-timeout to get the already changed text */
function delayedResize () {
window.setTimeout(resize, 0);
}
observe(text, 'change', resize);
observe(text, 'cut', delayedResize);
observe(text, 'paste', delayedResize);
observe(text, 'drop', delayedResize);
observe(text, 'keydown', delayedResize);
text.focus();
text.select();
resize();
}
Check 在这里拉小提琴。 http://jsfiddle.net/ZurAk/296/
