<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> <style> #oDiv{ width:100px; height:300px; background: #ccc; display: none; } </style> </head> <body> <!-- 點擊按鈕,執行一個函數,該函數控制div的顯示與隱藏,不用去獲取按鈕的id(getElementById) --> <input type="button" id = "btn" value = "點擊" onclick = "showHide()"> <div id = "oDiv"></div> </body> <script type="text/javascript"> function showHide(){ var oBtn = document.getElementById("btn"); var oDiv = document.getElementById("oDiv"); if(oDiv.style.display == "block"){ oDiv.style.display = "none"; //為什么這里的block要加引號,可以參考該處css中的display中的設置 css中display是key,value是block或者none,value是個字符串 那么肯定要加引號了。 }else{ oDiv.style.display = 'block'; } } </script> </html>