var autoTextarea = function (elem, extra, maxHeight) {
extra = extra || 0;
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.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();
};
var text = document.querySelectorAll("textarea");
for(var a=0;a<text.length;a++){
autoTextarea(text[a])
}