utf-8字符裁剪

slice_utf8str.js

function slice_utf8str(str, maxLen) {
  var len = str.length
  var _len = 0
  var i = 0
  for (; i < len; i++) {
    _len += str.charCodeAt(i) < 256 ? 1 : 2
    if (_len > maxLen) break
  }
  return str.slice(0, i)
}