<form>
<input type=hidden name=aa onclick="alert(123)">
<input type=button value=ok onclick="this.form.aa.click()">
</form>
<input type=hidden name=aa onclick="alert(123)">
<input type=button value=ok onclick="this.form.aa.click()">
</form>
<script>
a.click();
</script>
<input id="bb" type="button" onclick="alert('bb')">
<input id="aa" type="button" onclick="bb.click();">
<input id="bb" type="button" onclick="alert('bb')">