new Date('Thu Jun 15 2017 14:35:48 GMT+0800 (CST)').getTime()
附上一个函数

function parseTime (timeStamp, format) {
    var date = new Date(timeStamp);
    var o = {
        'M+' : date.getMonth() + 1, //month
        'D+' : date.getDate(), //day
        'h+' : date.getHours(), //hour
        'm+' : date.getMinutes(), //minute
        's+' : date.getSeconds(), //second
        'S' : date.getMilliseconds() //millisecond
    }

    if(/(Y+)/.test(format)) {
        format = format.replace(RegExp.$1,
            (date.getFullYear() + '').substr(4 - RegExp.$1.length));
    }

    for(var k in o) {
        if (new RegExp('('+ k +')').test(format)) {
            format = format.replace(RegExp.$1,
                RegExp.$1.length == 1 ? o[k] : ('00'+ o[k]).substr((''+ o[k]).length));
        }
    }
    return format;
}
// usage
parseTime(new Date.getTime(), 'hh:mm')