php和js互传cookie导致出现中文乱码的原因和解决措施

<?php
setcookie ("TestCookie", urlencode("这就是网页21"));
?>

<script type="text/javascript">
    alert(decodeURI(getCookie("TestCookie")))    
    function getCookie(sName) {    
    var aCookie = document.cookie.split('; ');    
    for (var i=0; i < aCookie.length; i++) {    
    var aCrumb = aCookie[i].split('=');    
    if (sName == aCrumb[0])    
    return decodeURI(aCrumb[1]);
 } return '';
}
</script>

<script type="text/javascript">function setCookie(name, value, time){    
        var nameString = name + '=' + encodeURI(value);    
        var expiryString = "";    
        if(time !== 0) {    
            var expdate = new Date();        
            if(time == null || isNaN(time)) time = 60*60*1000;
        expdate.setTime(expdate.getTime() +  time);
     expiryString = ' ;expires = '+ expdate.toGMTString();
 } 
 var path = " ;path =/";
 document.cookie = nameString + expiryString + path;
}setCookie("TestJsCookie", "我是中国人", 0)  </script>

<?php
echo urldecode($_COOKIE["TestJsCookie"]);
?>