js将匹配关键字使其变为红色

       /**
         * 将关键字变为红色
         * @param str  待处理字符串
         * @param keyWord   关键字字符串
         * @returns {*} 将关键字变为红色加粗后的字符串
         */
        function changeKeyRed(str,keyWord) {
            if(str!=null&&keyWord!=null){
                var substr="/"+keyWord+"/g";
                var replaceStr=str.replace(eval(substr),"<span style='color:red;font-weight:bold'>"+keyWord+"</span>")
                return replaceStr;
            }
            else {
                return str;
            }
        }

<p><span style='color:red;font-weight:bold'>keyWord</span>44444<span style='color:white;font-weight:bold;background:red'>666</span>77777<span style='color:blue;font-weight:bold'>666</span></p>