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| /**
* 统计区分中英文字符字数
*/
function getWordsCnt(str)
{
var n = 0;
var ch = 0;
for(var i = 0; i < str.length; i ++){
var ch = str.charCodeAt(i);
if (ch > 255) { // 中文字符集
n += 2;
ch = 1;
} else {
n ++;
}
}
if (ch == 1) {
if (n >= 23)
return 160;
if (n >= 19)
return 140;
if (n >= 15)
return 110;
if (n >= 10)
return 92;
if (n > 7)
return 80;
} else {
if (n >= 22)
return 150;
if (n >= 18)
return 135;
if (n >= 14)
return 110;
if (n >= 10)
return 90;
if (n > 7)
return 80;
}
return 0;
}
function autoTextarea (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 scrollTopp, 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'));
};
scrollTopp = document.body.scrollTopp || document.documentElement.scrollTopp;
elem.style.height = minHeight + 'px';
// 控制最小宽度
var minw = getWordsCnt(elem.value);
if (elem.style.minWidth < minw)
elem.style.minWidth = minw;
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';
scrollTopp += parseInt(style.height) - elem.currHeight;
document.body.scrollTopp = scrollTopp;
document.documentElement.scrollTopp = scrollTopp;
elem.currHeight = parseInt(style.height);
};
};
addEvent('propertychange', change);
addEvent('input', change);
addEvent('focus', change);
change();
}
|
