IE8 ajax 无法获取到token值，这是啥情况？

<body>

<input type="button" value=123" onclick="up();"/>

$.ajaxSetup({
    dataType: "json",
    cache: false,
    headers: {
        "token": "123"
    },
    error:function(err){
       
    }
    
});
function up(){
    alert(1)
    jQuery.support.cors = true; 
    $.ajax({
        type:'post',
        url:Router+'eccustomer/isNullPolicy',
        data:"1011596229328502786",
        contentType:'application/json;charset=UTF-8',
        async: true,
        success:function(res){  

        } 
    })
}

</script>
</body>

图片描述