My website is completely valid apart from target="_blank". Will having this 1 error make much difference in a search engines eyes? Are there any easy, valid alternatives available, preferably without using java?
The search engines certainly won't care. The only solutions available seem to be Javascript based ( http://www.sitepoint.com/article/standards-compliant-world/ ). I couldn't find any articles that suggested a non- Javascript solution. It seems to me that these XHTML 'standards' are pretty much what you would expect of anything developed by committee. The committee comes up with their pie-in-the-sky arsehat solutions, which are useless in the real world, and which the browsers, search engines, and any web developers with any sense in their head, completely ignore - and eventually the committee realizes its stupidity and changes the standard to reflect the needs of the real world. My suggestion would be to either switch to transitional mode, or just ignore the validator warnings.
There's a nice alternative called <a href="somelink">some link</a> : ) That is, no target at all. I do believe there are times when target or something similar is needed. Rare cases. Most of the time, it's someone not realizing how nasty it is on my computer to have 16 full-sized browsers, all stacked completely on top of each other (lots of people, tho mostly the tech-unsavvy, have their browsers full-screen). I'm computer-savvy enough to realise why my Back button doesn't work on those, but my mom sure wouldn't be (you don't necessarily realise a new window was opened if the new one sits exactly on top of the old one). If some site wants to open a whole new instance of my browser, they'd better have a damn good reason for it. The normal way for a link to work is it simply brings the user to the next page. If they love your site so much as to go back, they'll use the second-most-popular button ever: the back button. When I did a form that had some target="blank" links, I dropped down to Transitional doctype just for those pages (the rest are strict) because I felt it was more honest. I could have left them strict, nobody would have noticed except those who send my pages to the validator. Oh well. I didn't use the Javascript solution because the whole point of the target was to catch people who had no scripts, no browser caching, etc to prevent them from losing filled-in but unsubmitted form data. And, I sometimes think using a script to do a function that a browser is perfectly capable of doing is somehow wrong. It's like turning an anchor into href="#" and then using onclick events to do... what an anchor already does. And breaks it for those without scripts. Bleh. Iirc target was originally implemented for framed sites, so a link would go to another frame.