Why is DOMParser not preserving inline styles of p

问题:

I am simply trying to parse and append a JavaScript string as a DOM element. I have found two quick ways to do this, one of which is using DOMParser as seen in this popular SO answer. Both methods work, however, the DOMParser approach for some reason is not respecting the inline styles I define - even though both methods inject the exact same dynamic markup. Consider the following...

<div></div>

---

var parent = document.getElementsByTagName('div')[0]

// ---- case 1 ---------------

var parser = new DOMParser();
var node = parser.parseFromString('<p style="color: red">foo</p>', 'text/xml').firstChild;
parent.appendChild(node);

// ---- case 2 ---------------

var wrapper= document.createElement('div');
wrapper.innerHTML= '<p style="color: red">foo</p>';
var node2 = wrapper.firstChild;
parent.appendChild(node2);

Each method injects the node accordingly and the DOM reflects the following...

<div>
    <p style="color: red">foo</p>
    <p style="color: red">foo</p>
</div>

However, only the last is red! Any idea what can possibly be going on here?

---

JSFiddle - reproduction demo

回答1:

That's because you didn't set a namespace. style attributes don't have any special meaning in XML:

var str = '<p xmlns="http://www.w3.org/1999/xhtml" style="color: red">foo</p>';
var node = new DOMParser().parseFromString(str, 'text/xml').firstChild;
document.body.appendChild(node);

回答2:

CSS will be applied if you use the method like below.

var node = parser.parseFromString('<p style="color: red">foo</p>', 'text/html').firstChild.lastChild.firstChild;

here i am using 'text/html' As per the docs https://developer.mozilla.org/en/docs/Web/API/DOMParser using text/html returns a HTMLDocument.

fiddle: https://jsfiddle.net/wLnesqrb/8/

回答3:

var str = '<p style="color: red">foo</p>';
var frag = new DocumentFragment();
frag.innerHTML = str;
document.body.appendChild(frag);

But adding namespaces is safer if you want your code to work in XML documents too and not just HTML.