实现函数:
function isCharsInBag (s, bag)
{  
  var i,c;
  for (i = 0; i < s.length; i++)
  {   
        c = s.charAt(i);//字符串s中的字符
    if (bag.indexOf(c) > -1)
        return c;
  }
  return "";
}
检查函数:
function ischinese(s)
{
var errorChar;
var badChar = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789><,[]{}?/+=|\\'\":;~!#$%()`";
     errorChar = isCharsInBag( s, badChar)
        if (errorChar != "" )
    {
        report=report+"请重新输入中文\n";
        return false;
    }     
    
    return true;
}
就这么简单:)其实还输入日语,晕