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<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>本教程(w3big.com)</title> <script> function displayResult(){ var x=document.getElementById("button1").form.id; alert(x); } </script> </head> <body> <form id="form1"> <input type="button" onclick="displayResult()" value="显示包含按钮的表单id" id="button1"> </form> </body> </html>