问题:

I'm making an ajax get call that returns me contents of html page. I'm trying to select contents of the body tag but my selector returns an empty jquery object.

$.get(filename, function(data) {
    console.log($("body", data));
})

where data is contents of html file.

回答1:

jQuery cannot select body of the response string, because the <body> tag disappears when the string is converted using $().

Hence, you have to select the body from the data string in another way, such as Regular expressions. Example:

$.get(filename, function(data) {
    var body = data.replace(/^[\S\s]*<body[^>]*?>/i, "")
                    .replace(/<\/body[\S\s]*$/i, "");
    //Optionally, convert the string to a jQuery object:
    body = $(body);
    console.log(body);
}))

Note: My Regular Expression assumed a wellformed HTML document, where > are correctly shown using HTML entities. If this is not the case, more advanced RegExps has to be used, such as the ones shown at this question.

回答2:

jQuery uses the document object model, not the "text" that makes up that model. You only have a big piece of text in the data element that hasn't been added to the document yet.

$(body).html(data);

... assuming the data contains valid body code. It it's an entire HTML page, then you'll need to parse it for just the body content, e.g. using indexOf or somesuch.