How do I prevent DIV tag starting a new line?

The div tag is a block element, causing that behavior.

You should use a span element instead, which is inline.

If you really want to use div, add style="display: inline". (You can also put that in a CSS rule)

I am not an expert but try white-space:nowrap;

The white-space property is supported in all major browsers.

Note: The value "inherit" is not supported in IE7 and earlier. IE8 requires a !DOCTYPE. IE9 supports "inherit".