[JS] 버튼 백그라운드 색깔로 깜빡이게 하기

<script language="javascript" type="text/javascript"> 
<!-- 
/* 
Flashing text color Script- ? Dynamic Drive (www.dynamicdrive.com) 
Visit http://www.dynamicdrive.com for this script 
Credit must stay intact for use 
*/ 
//configure interval btw flash (1000=1 second) 
var speed=500 
function flashit(){ 
var crosstable=document.getElementById? document.getElementById("check_btn") : document.all? document.all.myexample : "" 
if (crosstable){ 
if (crosstable.style.backgroundColor.indexOf("rgb(12, 31, 51)")!=-1) 
crosstable.style.backgroundColor="#077af4" 
else 
crosstable.style.backgroundColor="rgb(12, 31, 51)" 
} 
} 
setInterval("flashit()", speed) 
//--> 
</script>




<button id="check_btn">깜빡임</button>