js判断输入的字符是否是汉字

<script type="text/javascript">
    var c=prompt("请输入一个字符");
    var isNumber = c>="0" && c<= "9";
    var isAlphabet = (c>="A" && c<="Z")||(c>="a" && c<="z");
    var isChinese = c>="\u4E00" && c<="\u9FA5";
    console.log("您输入的是数字吗?"+ isNumber +"\n"+
             "您输入的是字母吗？"+isAlphabet+"\n"+
                 "您输入的h汉字吗？"+isChinese);
</script>