js获取字符串字节长度

//返回val的字节长度 
function getByteLen(val) { 
  var len = 0; 
  for (var i = 0; i < val.length; i++) { 
    if (val[i].match(/[^\x00-\xff]/ig) != null) //全角 
        len += 2; 
    else 
        len += 1; 
  } 
  return len; 
} 

//返回val在规定字节长度max内的值 
function getByteVal(val, max) { 
  var returnValue = ‘‘; 
  var byteValLen = 0; 
  for (var i = 0; i < val.length; i++) { 
    if (val[i].match(/[^\x00-\xff]/ig) != null) 
      byteValLen += 2; 
    else 
      byteValLen += 1; 
    if (byteValLen > max) 
    break; 
    returnValue += val[i]; 
  } 
  return returnValue; 
}