Why is my domain prefixed to the value of href of <a> and/or the url of window.Open()

Question

Every so often (1/20) I use to have issues with the href value of a hyperlink being prefixed with my domain. Same goes for the url of window.open().

For example:

<a href="http://www.SomeURL.com" target="_blank">someURL</a>

OR

window.Open('http://www.SomeURL.com', '', ''); 

would open up a new browser tab and give me a 404 with the requested url of:
http://www.myDomain.com/http://www.SomeURL.com

As a work-around, I have my 404 error page get the requested url and if the requested url contains http://www.myDomain, I slice it then try to redirect again without my domain prefixed. I am guessing there is an actual solution to this though?

additional info
I have a gridView that list activities- some fields being: name, address, website ...etc. I use jQuery to get the URL of the gridView row that was clicked. I then insert that URL into a hyperlink inside of a span that is already on my page.

jQuery

var str = $("td:last", this).text();
$ ("#urlInfoLocation").html('< a id="urlLocation" target="_blank" href="' + str + '">' + str + '');

the span that is already on my page

< span id="urlInfo">

Answer 1

Another reason is you entered a unicode Right or Left Double Quotation Mark. Here's an example I found in my own page"

<a href=”https://www.youtube.com/watch?v=txLrNhv8GW0”>Q&A on Zone 2 Exercise with Peter Attia, M.D.

Just replace with a normal double quote.

Q&A on Zone 2 Exercise with Peter Attia, M.D.