js 判断 wifi and 流量

var connection = navigator.connection || navigator.mozConnection || navigator.webkitConnection || { tyep: ‘unknown‘ };
var type_text = [‘unknown‘, ‘ethernet‘, ‘wifi‘, ‘2g‘, ‘3g‘, ‘4g‘, ‘none‘];

alert(connection.type);
var re_el = document.getElementById("re");
var btn_el = document.getElementById("btn");
function get_status() {
    if (typeof (connection.type) == "number") {
        connection.type_text = type_text[connection.type];
    } else {
        connection.type_text = connection.type;
    }
    if (typeof (connection.bandwidth) == "number") {
        if (connection.bandwidth > 10) {
            connection.type = ‘wifi‘;
        } else if (connection.bandwidth > 2) {
            connection.type = ‘3g‘;
        } else if (connection.bandwidth > 0) {
            connection.type = ‘2g‘;
        } else if (connection.bandwidth == 0) {
            connection.type = ‘none‘;
        } else {
            connection.type = ‘unknown‘;
        }
    }
    var html = ‘Type : ‘ + connection.type_text;
    html += ‘Bandwidth : ‘ + connection.bandwidth;
    html += ‘isOnline : ‘ + navigator.onLine;
    re_el.innerHTML = html;
}

btn_el.onclick = function () {
    re_el.innerHTML = ‘Waiting...‘;
    get_status();
}