怎么动态改变背景图的url

Question

具体实现：    改变img-box中img的src打的同时能够立刻同步到bgimg，以背景图的形式展现，"background-image":"url($('.img-box img').attr('src').substring(0,20))"，这里的url要怎么写    <div class="bgimg"></div><div class="img-box">    <img src="img/2.jpg" alt=""></div>$(function(){        let h = document.documentElement.clientHeight;        $(".bgimg").height(h) + "px";        $(".bgimg").css({"background-image":"url($('.img-box img').attr('src').substring(0,20))"});        console.log($('.img-box img').attr('src').substring(0,20));                    })

Answer 1

$(".bgimg").css({'background-image':'url(' + $('.img-box img').attr('src').substring(0,20) + ')"'});