css 画个锯齿

.jag {
    width: 100px;
    height: 20px;
    background-image: linear-gradient(-45deg, darkblue 50%, transparent 50%),linear-gradient(45deg, darkblue 50%, transparent 50%);
    background-size: 10px 10px;
    background-color: transparent;
    background-repeat: repeat no-repeat;
}
                

效果如图：