If a string is passed as the parameter to $(), jQuery examines the string to see if it looks like HTML (i.e., it starts with <tag ... >). If not, the string is interpreted as a selector expression, as explained above. But if the string appears to be an HTML snippet, jQuery attempts to create new DOM elements as described by the HTML. Then a jQuery object is created and returned that refers to these elements. You can perform any of the usual jQuery methods on this object:
$( "<p id='test'>My <em>new</em> text</p>" ).appendTo( "body" );For explicit parsing of a string to HTML, use the $.parseHTML() method.
+By default, elements are created with an ownerDocument matching the document into which the jQuery library was loaded. Elements being injected into a different document should be created using that document, e.g., $("<p>hello iframe</p>", $("#myiframe").prop("contentWindow").document).
If the HTML is more complex than a single tag without attributes, as it is in the above example, the actual creation of the elements is handled by the browser's innerHTML mechanism. In most cases, jQuery creates a new <div> element and sets the innerHTML property of the element to the HTML snippet that was passed in. When the parameter has a single tag (with optional closing tag or quick-closing) — $( "<img />" ) or $( "<img>" ), $( "<a></a>" ) or $( "<a>" ) — jQuery creates the element using the native JavaScript createElement() function.
When passing in complex HTML, some browsers may not generate a DOM that exactly replicates the HTML source provided. As mentioned, jQuery uses the browser"s .innerHTML property to parse the passed HTML and insert it into the current document. During this process, some browsers filter out certain elements such as <html>, <title>, or <head> elements. As a result, the elements inserted may not be representative of the original string passed.
Filtering isn't, however, limited to these tags. For example, Internet Explorer prior to version 8 will also convert all href properties on links to absolute URLs, and Internet Explorer prior to version 9 will not correctly handle HTML5 elements without the addition of a separate compatibility layer.