form中限制文本字节数js代码

添加（1）onkeyup="limitLength(this.value,100,'名称','name')"
(2)id="name"或【struts标签】styleId="name"
注意：id名称和attribute属性名称要一样

例子：

或

*/

functionlimitLength(value,byteLength,title,attribute){
varnewvalue=value.replace(/[^x00-xff]/g,"**");
varlength=newvalue.length;

//当填写的字节数小于设置的字节数
if(length*1<=byteLength*1){
return;
}
varlimitDate=newvalue.substr(0,byteLength);
varcount=0;
varlimitvalue="";
for(vari=0;ivarflat=limitDate.substr(i,1);
if(flat=="*"){
count++;
}
}
varsize=0;
varistar=newvalue.substr(byteLength*1-1,1);//校验点是否为“×”

//if基点是×;判断在基点内有×为偶数还是奇数
if(count%2==0){
//当为偶数时
size=count/2+(byteLength*1-count);
limitvalue=value.substr(0,size);
}else{
//当为奇数时
size=(count-1)/2+(byteLength*1-count);
limitvalue=value.substr(0,size);
}
alert(title+"最大输入"+byteLength+"个字节（相当于"+byteLength/2+"个汉字）！");
document.getElementById(attribute).value=limitvalue;
return;
}