背景图片固定不随页面上下滚动而滚动 ,属性 background-attachment
<div id="testimonials-section" class="text-center"> </div>
css:
#testimonials-section {
background: url(../img/testimonial-bg.jpg);
background-size: cover;
background-position: top;
background-attachment: fixed;
background-repeat: no-repeat;
color: #ffffff;
padding: 80px 0;
}