Js解析时间字符串

var timeSegment = $("#timeend").val().split(/[- :]/);
for(var i in timeSegment){
    if((i == 0 && timeSegment[i].length != 4) || (i != 0 && timeSegment[i].length > 2)){
        alert('结束时间格式不正确!');
        return false;
    }
}
isNaN(Date.parse($("#timestart").val().replace(/-/g,'/')))