要在on click事件中调用多个JavaScript函数，请使用分号，如下所示-
onclick="Display1();Display2()"
<html>
<head>
<script>
function Display1() {
document.write ("你好！");
}
function Display2() {
document.write ("你好，世界！");
}
</script>
</head>
<body>
<p>Click the following button to call the function</p>
<form>
<input type = "button" onclick = "Display1(); Display2()" value = "Result">
</form>
</body>
</html>