form中限制文本字节数js代码

/*
value: 值；
byteLength：数据库字节长度
title：字段中文名称
attribute：属性名称
使用方法说明：

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：

<br><br> 或 <br><br><input type="text"   name="explain"  id="explain" onkeyup="limitLength(value,5,'语义说明','explain')" > <br><br>*/ <br><br><br><br>function limitLength(value, byteLength, title, attribute) { <BR>       var newvalue = value.replace(/[^\x00-\xff]/g, "**"); <BR>       var length = newvalue.length; <br><br>       //当填写的字节数小于设置的字节数 <BR>      if (length * 1 <=byteLength * 1){ <BR>            return; <BR>      } <BR>      var limitDate = newvalue.substr(0, byteLength); <BR>      var count = 0; <BR>      var limitvalue = ""; <BR>     for (var i = 0; i < limitDate.length; i++) { <BR>             var flat = limitDate.substr(i, 1); <BR>            if (flat == "*") { <BR>                  count++; <BR>            } <BR>     } <BR>     var size = 0; <BR>     var istar = newvalue.substr(byteLength * 1 - 1, 1);//校验点是否为“×” <br><br>    //if 基点是×; 判断在基点内有×为偶数还是奇数  <BR>     if (count % 2 == 0) { <BR>              //当为偶数时 <BR>            size = count / 2 + (byteLength * 1 - count); <BR>            limitvalue = value.substr(0, size); <BR>    } else { <BR>            //当为奇数时 <BR>            size = (count - 1) / 2 + (byteLength * 1 - count); <BR>            limitvalue = value.substr(0, size); <BR>    } <BR>   alert(title + "最大输入" + byteLength + "个字节（相当于"+byteLength /2+"个汉字）！"); <BR>   document.getElementById(attribute).value = limitvalue; <BR>   return; <BR>}  </div>

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form中限制文本字节数js代码_表单特效