Choosing a language for use webpage data

I have a project where i will use a website data, this website don't have API, so i have to parse data, but i will need request data constantly, basically i need interact with the website.

Example about what i need: Me: website give me the current items on sale Website: item1, item2, item3, ..., itemN Me: (checking prices), alright bid for the item1, etc

I need do this constantly and each millisecond is really importan for me. I need make an robust application and i need a language with the following requirements:

• Good concurrency
• Good performance
• Good web library support
• Moderate time of learning and development
• Preferable a modern language

I would like to use a language like Go, Scala or D but i'm open to all suggestions.

I hope that what i ask dont be ambiguous, thanks.