When registering a click event for a, there is a default behavior, the way to prevent the default behavior: retrun false
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<a href="">Click to print in console hahaha</a>
<script>
// 1. Get a
var link = document.getElementsByTagName('a')[0 ];
// 2. Register a click event for a
link.onclick = function (){
console.log( 'Hahaha' );
console.log(1);
return false ; // To prevent the default behavior of the a tag, write return false in the last line of the event handler
}
</script>
</body>
</html>