Regex to get src value from an img tag

Question

I am using the following regex to get the src value of the first img tag in an HTML document.

string match = "src=(?:\"|\')?(?<imgSrc>[^>]*[^/].(?:jpg|png))(?:\"|\')?"

Now it captures total src attribute that I dont need. I just need the url inside the src attribute. How to do it?

Answer 1

Parse your HTML with something else. HTML is not regular and thus regular expressions aren't at all suited to parsing it.

Use an HTML parser, or an XML parser if the HTML is strict. It's a lot easier to get the src attribute's value using XPath:

//img/@src

XML parsing is built into the System.Xml namespace. It's incredibly powerful. HTML parsing is a bit more difficult if the HTML isn't strict, but there are lots of libraries around that will do it for you.

Answer 2

Your regex should (in english) match on any character after a quote, that is not a quote inside an tag on the src attribute.

In perl regex, it would be like this:

/src=[\"\']([^\"\']+)/

The URL will be in $1 after running this.

Of course, this assumes that the urls in your src attributes are quoted. You can modify the values in the [] brackets accordingly if they are not.

Answer 3

see When not to use Regex in C# (or Java, C++ etc) and Looking for C# HTML parser

PS, how can I put a link to a StackOverflow question in a comment?