回傳當前文件的 <head> 元素。如果該文件有超過一個 <head> 元素，那只會回傳第一個 <head> 元素。
語法
var objRef = document.head;
範例
// in HTML: <head id="my-document-head">
var aHead = document.head;
alert(aHead.id); // "my-document-head";
alert( document.head === document.querySelector("head") ); // true
備註
document.head 是「唯讀」。若是想要將 document.head 改成別的值會失敗，這時有些瀏覽器不會告知任何錯誤訊息；有些，例如在 ECMAScript Strict 模式下 的 Gecko 瀏覽器，會給出 TypeError 異常。
規範
| Specification | Status | Comment |
|---|---|---|
| HTML Living Standard The definition of 'Document.head' in that specification. |
Living Standard | Initial definition. |
| HTML 5.1 The definition of 'Document.head' in that specification. |
Recommendation | |
| HTML5 The definition of 'Document.head' in that specification. |
Recommendation |
瀏覽器相容性
We're converting our compatibility data into a machine-readable JSON format.
This compatibility table still uses the old format,
because we haven't yet converted the data it contains.
Find out how you can help!
| Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | 4.0 | (Yes) | 4.0 (2) | 9.0 | 11.0 | 5.0 |
| Feature | Android | Edge | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|
| Basic support | (Yes) | (Yes) | 4.0 (2) | 9.0 | (Yes) | (Yes) |