var CSSrules = {
'textarea' : function(element){
element.onkeydown = function(event){
return doKeyPress(element,event);
}
,
element.onpaste = function(){
return doPaste(element);
}
,
element.onkeyup = function(){
return doKeyUp(element);
}
,
element.onblur = function(){
return doKeyUp(element);
}
}
}Behaviour.register(CSSrules);var detect = navigator.userAgent.toLowerCase();// Keep user from entering more than maxLength characters
function doKeyPress(obj,evt){//键入时
maxLength = obj.getAttribute("maxlength");
var e = window.event ? event.keyCode : evt.which;
if ( (e == 32) || (e == 13) || (e > 47)) { //IE
if(maxLength && (obj.value.length > maxLength-1)) {
if (window.event) {
window.event.returnValue = null;
} else {
evt.cancelDefault;
return false;
}
}
}
}
function doKeyUp(obj){//按键时
maxLength = obj.getAttribute("maxlength");
if(maxLength && obj.value.length > maxLength){
obj.value = obj.value.substr(0,maxLength);
}
sr = obj.getAttribute("showremain");
if (sr) {
document.getElementById(sr).innerHTML = maxLength-obj.value.length;//sr是剩余可添加字符数
}
}// Cancel default behavior and create a new paste routine
function doPaste(obj){ //复制时
maxLength = obj.getAttribute("maxlength");
if(maxLength){
if ((window.event) && (detect.indexOf("safari") + 1 == 0)) { //IE
var oTR = obj.document.selection.createRange();
var iInsertLength = maxLength - obj.value.length + oTR.text.length;
try {
var sData = window.clipboardData.getData("Text").substr(0,iInsertLength); //截断多余的字符
oTR.text = sData;
}
catch (err) {
}
if (window.event) { //IE
window.event.returnValue = null;
} else {
//not IE
obj.value = obj.value.substr(0,maxLength);
return false;
}
}
}
}