可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试):

问题:

I'm trying to learn jQuery's ajax functions. I've got it working, but jQuery doesn't find elements in the returned HTML DOM. In the same folder as jquery, run this page:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
    <title>runthis</title>

    <script type="text/javascript" language="javascript" src="jquery-1.3.2.min.js"></script>

    <script tyle="text/javascript">
    $(document).ready(function(){
        $('input').click(function(){
            $.ajax({
                type : "GET",
                url : 'ajaxtest-load.html',
                dataType : "html",
                success: function(data) {

                alert( data ); // shows whole dom

                alert( $(data).find('#wrapper').html() ); // returns null

                },
                error : function() {
                    alert("Sorry, The requested property could not be found.");
                }
            });
        });
    });
    </script

</head>
<body>
    <input type="button" value="load" />
</body>
</html>

Which loads this page "ajaxtest-load.html":

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
    <title>load this</title>

</head>
<body>
    <div id="wrapper">
    test
    </div>
</body>
</html>

It gives two alerts. One showing the DOM was loaded, but the second shows NULL instead of the #wrapper. What am I doing wrong?

EDIT: I'm loading "ajaxtest-load.html" which includes the whole header, including jquery again. Is that the issue?

回答1:

I've managed to load snippets off of full html-documents just fine by using .load().

To create a new block with extracted html into the DOM I do this:

$('<div></div>').appendTo('body').load('some-other-document.html div#contents');

If it's not working for you, make sure you're using the most recent version (or post 1.2) of jQuery. See the documentation for .load for more examples.

Edit:

Note, though, that with the above example the result will be:

<div><div id="contents">...</div></div>

To get just the contents of the #contents div in the other document, use a callback-function in the load-function call.

$('<div></div>').load('some-other-document.html div#contents', null, 
    function (responseText, textStatus, XMLHttpRequest) {
        if (textStatus == success) {
            $('<div></div>').appendTo('body').html($(this).html());
        }
    }
);

回答2:

This is not a direct answer, but may help to clarify things.

The data parameter of the callback function can be made into a jQuery (1.6.2) object $(data), which contains the different parts of the HTML response:

Stuff that precedes the actual document, such as a doctype declaration, or ignorable white space textnodes.
The contents of the head element.
The contents of the body element.

The html, head and body elements are not in the data object. Since the number of elements contained in head and body may vary, you should not get them by indexing like $(data)[2]. Instead, apply a filter to this object, like this:

        $.get(
          uri,
          function(data, textStatus, jqXHR){
            var $doc = $(data);
            var title = $doc.filter('title').text();
            // title is the title from the head element.
            // Do whatever you need to do here.
          }
        );

After filtering the right elements, you can apply further selectors using find().

Unfortunately, in IE the head elements are not part of $(data). I have no idea why this is.

回答3:

I found that if ajaxtest-load.html does not have <html> or <body> tags but just a few html elements, it does work.

Edit:

If the input has to be a full HTML page, maybe you can first strip of the tags you don't want with string operations.. anyone?

Edit 2:

Vaguely remembered Javascript/DOM allowed for "temporary documents" which you could operate on and use the results from, then a bit of googling yielded a parseHTML function (http://www.daniweb.com/forums/post874892-2.html) which I've adapted to return the right bit:

$(document).ready(function(){
  $('input').click(function(){
    $.ajax({
      type : "POST",
      url : 'ajaxtest-load.html',
      dataType : "html",
      success: function(data) {
        alert( data ); // shows whole dom
        var gotcha = parseHTML(data, 'wrapper');
        if (gotcha) {
          alert($(gotcha).html());
        }else{
          alert('ID not found.');
        }
      },
      error : function() {
        alert("Sorry, The requested property could not be found.");
      }
    });
  });
});

function parseHTML(html, idStr) {
  var root = document.createElement("div");
  root.innerHTML = html;
  // Get all child nodes of root div
  var allChilds = root.childNodes;
  for (var i = 0; i < allChilds.length; i++) {
    if (allChilds[i].id && allChilds[i].id == idStr) {
      return allChilds[i];
    }
  }
  return false;
}

Does that work?

回答4:

Why not try this and see what happens:

$('#testDiv').load('ajaxtest-load.html #wrapper', function(resp) {
    alert(resp);
});

From the $.load documentation:

In jQuery 1.2 you can now specify a jQuery selector in the URL. Doing so will filter the incoming HTML document, only injecting the elements that match the selector.