转换时间戳与时间截取

//时间截取与转换时间戳

function timeChange(timeStamp) {
    var newDate = new Date(timeStamp);
    Date.prototype.format = function (format) {
        var date = {
            "M+": this.getMonth() + 1,
            "d+": this.getDate(),
            "h+": this.getHours(),
            "m+": this.getMinutes(),
            "s+": this.getSeconds(),
            "q+": Math.floor((this.getMonth() + 3) / 3),
            "S+": this.getMilliseconds()
        };
        if (/(y+)/i.test(format)) {
            format = format.replace(RegExp.$1, (this.getFullYear() + '').substr(4 - RegExp.$1.length));
        }
        for (var k in date) {
            if (new RegExp("(" + k + ")").test(format)) {
                format = format.replace(RegExp.$1, RegExp.$1.length == 1
                        ? date[k] : ("00" + date[k]).substr(("" + date[k]).length));
            }
        }
        return format;
    };
    var time = newDate.format('yyyy-MM-dd hh:mm:ss');//查找时间点,转换成时间类型
    return time;
}
var tim= 1469980800000;
var newT=timeChange(tim).substr(8,8).replace(" ","日");
console.log(newT);

var time=(timeChange(tim-7*1000*24*60*60).substr(5,5)).replace("-"," ")+"～"+(timeChange(tim).substr(5,5)).replace("-"," ");
console.log(time);
var time1=(timeChange(tim-7*1000*24*60*60).substr(5,5)).replace("-","")+"～"+(timeChange(tim).substr(5,5)).replace("-","");
console.log(time1);