console 命令行工具 X clear

console

   function keywordscolorful(str, key){
        var reg = new RegExp("(" + key + ")", "g");
        var newstr = str.replace(reg, "<span style='background:#ff0;'>$1</span>");
        return newstr;
    }
 
 let str = document.getElementById("demo").innerHTML
 let key = "中国" 
 var demo = keywordscolorful(str, key);
 console.log(demo)
document.getElementById("demo").innerHTML = demo;

<div class="domo" id="demo">我爱中国</div>