String.prototype.len=function(){return this.replace([^\x00-\xff]/g,"aa").length;}

String.prototype.trim = function()
{
  return this.replace(/(^\s*)|(\s*$)/g, "");
}

function IP2V(ip)
{
 re=/(\d+)\.(\d+)\.(\d+)\.(\d+)/g //匹配IP地址的正则表达式
if(re.test(ip))
{
return RegExp.1∗Math.pow(255,3))+RegExp.2*Math.pow(255,2))+RegExp.3∗255+RegExp.4*1
}
else
{
 throw new Error("Not a valid IP address!")
}
}

var ip="10.100.20.168"
ip=ip.split(".")
alert("IP值是："+(ip[0]*255*255*255+ip[1]*255*255+ip[2]*255+ip[3]*1))

var s="abacabefgeeii"
var s1=s.replace(/(.).*\1/g,"$1")
var re=new RegExp("["+s1+"]","g")
var s2=s.replace(re,"") 
alert(s1+s2) //结果为：abcefgi

s="http://www.9499.net/page1.htm"
s=s.replace(/(.*\/){0,}([^\.]+).*/ig,"$2")
alert(s)

onkeyup="value=value.replace(/[^\u4E00-\u9FA5]/g,'')" onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\u4E00-\u9FA5]/g,''))"

 onkeyup="value=value.replace(/[^\uFF00-\uFFFF]/g,'')" onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\uFF00-\uFFFF]/g,''))"

onkeyup="value=value.replace(/[^\d]/g,'') "onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\d]/g,''))"

onkeyup="value=value.replace(/[\W]/g,'') "onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\d]/g,''))"

/**
 * 计算字符串长度，将非宽字符计算为半个字符
 * 
 * @param str
 * @returns
 */
function gbLength(str) {
  return typeof str === "string" ? str.length + str.replace(/[\x00-\x7f]/g, '').length + 1 >> 1 : 0;
}

/**
 * 获取字符串的指定长度的子串，将非宽字符计算为半个字符
 * 
 * @param str
 * @param length
 * @returns
 */
function gbSubstr(str, length) {
  if (typeof str !== "string")
    return str;
  length += length;
  for ( var n = 0, L = str.length; n < L && length > 0; n++){
    length -= str.charCodeAt(n) > 127 ? 2 : 1;
  }
  return str.substr(0, n);
}
/**
 * 切割指定字符串的指定长度子串，如果长度超过指定长度，则丢弃末尾两个字符并附加...
 * 
 * @param str
 * @param len
 * @returns
 */
function fit_length(str, len){
  len = len || 16;
  if (typeof str !== "string" || str.length <= len || gbLength(str) <= len){
    return str;
  }
  var ret = gbSubstr(str, len - 2);
  return ret + '..';
}
var replaceCJK = /[^\x00-\xff]/g,
  testCJK  = /[^\x00-\xff]/;

    cjkLength: function(strValue){
      return strValue.replace(replaceCJK, "lv").length;
    },
    isCjk: function(strValue){
      return testCJK.test(strValue);
    },
    cutString: function(str,len,suffix,slen){
      suffix = suffix || '';
      slen = slen || suffix.length;
      if(str.length > len){
        str = str.substr(0,len - slen) + suffix;
      }
      return str;
    },
    cutCjkString: function(str,len,suffix,slen){
      suffix = suffix || '';
      slen = slen || suffix.length;
      len -= slen;
      if(this.cjkLength(str) <= len){
        return str;
      }
      var s = str.split(''),c = 0,tmpA = [];
      for(var i=0;i<s.length;i+=1){
        if(c < len){
          tmpA[tmpA.length] = s[i];
        }
        if(this.isCjk(s[i])){
          c += 2;
        }else{
          c += 1;
        }
      }
      return tmpA.join('') + suffix;
    }
  }