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I am currently getting response error in html format. It is of type string.

"<!DOCTYPE html>\r\n
<html>
  <head>
    <title>Data already exists</title>
  </head>
</html>"

I wanted to retrieve the content inside the <title>, for above instance "Data already exists". Can anybody suggest a appropriate regular expression to capture that text.

Please any help is appreciated!

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  • I really appreciate everyone's suggestion and thanks for taking time to share the knowledge. You guys are awesome. Commented Aug 29, 2012 at 14:07

3 Answers 3

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5

First, you can do it without regex, by creating a dummy element to inject the HTML:

var s = "your_html_string";
var dummy = document.createElement("div");
dummy.innerHTML = s;
var title = dummy.getElementsByTagName("title")[0].innerText;

But if you really insist on using regex:

var s = "your_html_string";
var title = s.match(/<title>([^<]+)<\/title>/)[1];

Here's a DEMO illustrating both approaches.

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5 Comments

You don't need to use getElementsByTagName, there is a document.title property that is more convenient. Also, the title element can have attributes, so the regular expression needs to be more sophisticated (parsing HTML with a regular expression is generally a bad idea).
@RobG: I absolutely agree that parsing HTML with a regex is generally a bad idea; however, OP explicitly said that it it was a response error that follows the above format. document.title will get the current document's title. Note that OP is no trying to parse the current document but a specific response message (probably from an ajax call).
Hmm... One line of regex, or three lines of dummy element manipulation? One or three? I know which I'd choose. (I too agree that in a general sense parsing HTML with regex is not the way to go, but as you said João, for a specific case with a known format I think it is OK.)
Yes, all good. The OP could use the response text to create a new document, then just use document.title.
I really appreciate everyone's suggestion and thanks for taking time to share the knowledge. You guys are awesome.
2

The very basics of parsing html tags in regex is this. http://jsbin.com/oqivup/1/edit

var text = /<(title)>(.+)<\/\1>/.exec(html).pop();

But for more complicated stuff I would consider using a proper parser.

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2 Comments

Given the response is already a string can't you skip the jQuery line?
I really appreciate everyone's suggestion and thanks for taking time to share the knowledge. You guys are awesome.
1

You could parse it using DOMParser():

var parser=new DOMParser(),
    doc=parser.parseFromString("<!DOCTYPE html><html><head><title>Data already exists</title></head></html>","text/html");

doc.title; /* "Data already exists" */
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10 Comments

You probably need to use an ActiveXObject for IE < 9.
and how we can use the doc variable with jquery?
@DariushJafari Do you mean $(doc)?
Chrome 23 Canary doesn't parse HTML with DOMParser though. If the HTML string is XML-valid, you can always use the application/xml parsing for cross-browser parsing.
@Oriol how do you select some elements of doc? $('div.cc') selects the current document elements.
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