JavaScript问题

Question

<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，能不能详细的讲解一下