文本框根据输入内容自适应高度的代码
程序员文章站
2023-12-09 23:13:39
其实现代浏览器大多都支持文本框尺寸调节功能，绝大多数情况下却没有自动适应来得爽快，在网络上发现一方法比较简单的实现文本框高度自适应，于是封装了这个函数，准备以后应用到项目中。 源代码： 23:03文章...
其实现代浏览器大多都支持文本框尺寸调节功能，绝大多数情况下却没有自动适应来得爽快，在网络上发现一方法比较简单的实现文本框高度自适应，于是封装了这个函数，准备以后应用到项目中。
源代码：
23:03文章更新：
感谢alucelx同学再次给力的帮助，大大简化了方法，更新代码为0.2版本，同时解决了兼容opera浏览器，至此全兼容ie6+与现代浏览器！
在线演示： http://demo.jb51.net/js/2011/autoarea/index.htm
autotextarea.js
/**
* 文本框根据输入内容自适应高度
* @author tang bin
* @version 0.3
* @see http://www.planeart.cn/?p=1489
* @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();
};
测试代码：
<!doctype html>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>文本框根据输入内容自适应高度</title>
<style type="text/css">
#textarea { font: 1.4em/1.8em arial; overflow: hidden; width: 550px; height: 6em; padding:10px; }
</style>
<script src="autotextarea.js"></script>
</head>
<body style="background:#fbfcfd url(http://goo.gl/klszx);">
<textarea id="textarea"></textarea>
<script>
var text = document.getelementbyid("textarea"),
tip = '想写点什么..';
autotextarea(text);// 调用
text.value = tip;
text.onfocus = function () {
if (text.value === tip) text.value = '';
};
text.onblur = function () {
if (text.value === '') text.value = tip;
};
</script>
</body>
</html>
源代码：
23:03文章更新：
感谢alucelx同学再次给力的帮助，大大简化了方法，更新代码为0.2版本，同时解决了兼容opera浏览器，至此全兼容ie6+与现代浏览器！
在线演示： http://demo.jb51.net/js/2011/autoarea/index.htm
autotextarea.js
复制代码 代码如下:
/**
* 文本框根据输入内容自适应高度
* @author tang bin
* @version 0.3
* @see http://www.planeart.cn/?p=1489
* @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();
};
测试代码：
<!doctype html>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>文本框根据输入内容自适应高度</title>
<style type="text/css">
#textarea { font: 1.4em/1.8em arial; overflow: hidden; width: 550px; height: 6em; padding:10px; }
</style>
<script src="autotextarea.js"></script>
</head>
<body style="background:#fbfcfd url(http://goo.gl/klszx);">
<textarea id="textarea"></textarea>
<script>
var text = document.getelementbyid("textarea"),
tip = '想写点什么..';
autotextarea(text);// 调用
text.value = tip;
text.onfocus = function () {
if (text.value === tip) text.value = '';
};
text.onblur = function () {
if (text.value === '') text.value = tip;
};
</script>
</body>
</html>