推荐使用:
/** * textarea高度自动适应内容的高度 * @param obj dom 元素,可以是 $('#content')[0] 或者 document.getElementById('content') */ function autoTextAreaHeight(obj) { let style = window.getComputedStyle(obj, null); obj.style.height = obj.scrollTop + obj.scrollHeight - parseFloat(style.getPropertyValue('padding-top')) - parseFloat(style.getPropertyValue('padding-bottom')) + 'px'; }
然后在需要调用的页面输入如下代码:
$(function () { var infoTextarea = $('#info');//textarea的id属性为info infoTextarea.on('input', function () { autoTextAreaHeight(infoTextarea[0]); }); autoTextAreaHeight(infoTextarea[0]); });
下面是在网络上发现的一个封装函数,全兼容IE6+与现代浏览器!具体函数代码如下(可以看看实现方法,不推荐使用):
/** * 文本框根据输入内容自适应高度 * @author tang bin * @version 0.3 * @see https://www.phpernote.com/jquery/32.html * @param {HTMLElement} 输入框元素 * @param {Number} 设置光标与输入框保持的距离(默认20) * @param {Number} 设置最大高度(可选) */ var autoTextarea = function (elem, extra, maxHeight) { extra = extra || 20; var isFirefox = !!document.getBoxObjectFor || 'mozInnerScreenX' in window, isOpera = !!window.opera && !!window.opera.toString().indexOf('Opera'), addEvent = function (type, callback) { elem.addEventListener ? elem.addEventListener(type, callback, false) : elem.attachEvent('on' + type, callback); }, getStyle = elem.currentStyle ? function (name) { var val = elem.currentStyle[name]; if (name === 'height' && val.search(/px/i) !== 1) { var rect = elem.getBoundingClientRect(); return rect.bottom - rect.top - parseFloat(getStyle('paddingTop')) - parseFloat(getStyle('paddingBottom')) + 'px'; }; return val; } : function (name) { return getComputedStyle(elem, null)[name]; }, minHeight = parseFloat(getStyle('height')); elem.style.maxHeight = elem.style.resize = 'none'; var change = function () { var scrollTop, height, padding = 0, style = elem.style; if (elem._length === elem.value.length) return; elem._length = elem.value.length; if (!isFirefox && !isOpera) { padding = parseInt(getStyle('paddingTop')) + parseInt(getStyle('paddingBottom')); }; scrollTop = document.body.scrollTop || document.documentElement.scrollTop; elem.style.height = minHeight + 'px'; if (elem.scrollHeight > minHeight) { if (maxHeight && elem.scrollHeight > maxHeight) { height = maxHeight - padding; style.overflowY = 'auto'; } else { height = elem.scrollHeight - padding; style.overflowY = 'hidden'; }; style.height = height + extra + 'px'; scrollTop += parseInt(style.height) - elem.currHeight; document.body.scrollTop = scrollTop; document.documentElement.scrollTop = scrollTop; elem.currHeight = parseInt(style.height); }; }; addEvent('propertychange', change); addEvent('input', change); addEvent('focus', change); change(); };
调用方法如下(textarea_id为textarea的id值):
autoTextarea(document.getElementById('textarea_id'));
另外一种简易的实现方法:
<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>TEXTAREA自适应文字行数的多少</title> </head> <body> <textarea rows="6" name="s1" cols="27" onpropertychange="this.style.posHeight=this.scrollHeight"></textarea> </body> </html>