更新： –
过渡5秒.

过渡：宽度5s易于进出;

$('.progress-bar-fill').delay(1000).queue(function () {
        $(this).css('width','100%')
    });

.progress-bar {
    width: calc(100% - 6px);
    height: 5px;
    background: #e0e0e0;
    padding: 3px;
    border-radius: 3px;
    Box-shadow: inset 0 1px 3px rgba(0,.2);
}

.progress-bar-fill {
    display: block;
    height: 5px;
    background: #659cef;
    border-radius: 3px;
    /*transition: width 250ms ease-in-out;*/
    transition: width 5s ease-in-out;
}