<script> var buttons=document.getElementsByTagName("button") for(var i=0;i<buttons.length;i++){ buttons[i].onclick=function(e){ var elem=document.getElementById("fruittext"); if(e.target.innerHTML=="Outline Off"){ elem.style.outline="none" } else{ elem.style.outlineColor="red"; elem.style.outlineStyle="solid"; elem.style.outlineWidth="thick"; } }; }</script>我看不太懂，能不能詳細的講解一下