SOURCE

var buvid = prompt('请输入buvid')
var a = parseFloat(buvid)
var b = isNaN(a) ? buvid : a
var c = parseInt(b.toString().substr(0, 1), 16) <= 8;
if (c) {
    alert("该buvid符合要求")
} else {
    alert("该buvid不符合要求")
}