使用Javascript将HTML的DocType作为字符串 | 使用Javascript将HTML的DocType作为字符串

本文介绍了使用Javascript将HTML的DocType作为字符串的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我知道我可以通过 document.doctype 或 document.childNodes [0] 访问doctype对象我的问题是将doctype作为一个字符串。我可以通过调用 document.doctype 返回<！DOCTYPE html PUBLIC - // W3C // DTD HTML 4.01 // ENhttp://www.w3.org/TR/html4/strict.dtd> 。但是在Firefox中，调用 document.doctype 返回DocumentType对象。

I know that I can access to doctype object via document.doctype or document.childNodes[0] but my problem is getting doctype as a string. I can do this in chrome and safari by calling document.doctype which returns <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">. However in Firefox, calling document.doctype returns DocumentType object.

有没有办法在chrome和safari中获得所有浏览器中的doctype字符串？

Is there a way to get the the doctype string in all browsers as in chrome and safari?

谢谢

推荐答案

在所有兼容的浏览器（包括Chrome / Safari）中，还返回一个对象，请访问w3.org/TR/DOM-Level-3-Core/core.html#ID-412266927rel =noreferrer> 以下代码可用于生成有效的DOCTYPE字符串。

In all compliant browsers (including Chrome/Safari), document.doctype also returns a DocumentType object. The following code can be used to generate a valid DOCTYPE string.

var node = document.doctype;
var html = "<!DOCTYPE "
         + node.name
         + (node.publicId ? ' PUBLIC "' + node.publicId + '"' : '')
         + (!node.publicId && node.systemId ? ' SYSTEM' : '')
         + (node.systemId ? ' "' + node.systemId + '"' : '')
         + '>';

此方法返回正确的字符串，例如：

This method returns the correct string for valid (HTML5) doctypes, eg:

 
  <！DOCTYPE html>  
 
  <！DOCTYPE html SYSTEMabout：legacy-compat> code> 
 
  <！DOCTYPE HTML PUBLIC -  // W3C // DTD HTML 4.0 // ENhttp：//www.w3 .org / TR / REC-html40 / strict.dtd>

<!DOCTYPE html>
<!DOCTYPE html SYSTEM "about:legacy-compat">
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">

代码说明：

node.name      # Holds the name of the root element, eg: HTML / html
node.publicId  # If this property is present, then it's a public document type.
               #>Prefix PUBLIC
!node.publicId && node.systemId
               # If there's no publicId, but a systemId, prefix SYSTEM
node.systemId  # Append this if present

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