The button button under Firefox has a child element canvas to bind the click event to canvas, and the click is invalid. What is the reason for this?

The button button under

Firefox has a child element canvas to bind the click event to canvas, and the click is invalid. What is the reason for this? Just change the button tag to div . The test code is as follows:

<body>
<button>
   <canvas id="cav" style="width: 100px; height: 100px; border: 1px solid -sharp000;"></canvas>
</button>
</body>
<script>
 var a = document.getElementById("cav");
 a.onclick = function() {
    console.log("aaa"); // Firefox / IE9+ 
 }
</script>
Jun.16,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1e478e1-4397b.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1e478e1-4397b.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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