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<p id="demo">单击按钮显示2的自然对数</p>2
<button onclick="myFunction()">点我</button>3
<script>4
function myFunction() {5
document.getElementById("demo").innerHTML = Math.LN2;6
}7
</script>
<p id="demo">单击按钮显示2的自然对数</p><button onclick="myFunction()">点我</button><script> function myFunction() { document.getElementById("demo").innerHTML = Math.LN2; }</script>