来源:http://www.jb51.net/article/42468.htm
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 autoTextarea (elem) {
var text = document.getElementById(elem);
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();
}
// 调用
autoTextarea('myTextareaId');