tinuxer

<script>
var h='<img src="/bb/sfffs" /><img src="/bbss/ss" /><img src="/btb/srs" /><img src="/bbgg/ss" /><p><img alt="" src="/media/upload/2019/05/29/g2.png" style="height:128px; width:128px" /></p>'


function changesrc(htmlstr,addurl) {  
    var reg = /<img.+?src=('|")?([^'"]+)('|")?(?:\s+|>)/gim;  

    while (tem = reg.exec(htmlstr)) {  
       htmlstr=htmlstr.replace(tem[2],addurl+tem[2]);  
    }  
    return htmlstr;  
}

alert(changesrc(h,"http://127.0.0.1"))
</script>