If you mean a style from the style attribute, you can access them directly on the element instance:
var color = this.style.color;
That will give you the color only if it's in the style attribute (not applied via stylesheet).
The names you use are camelCase if you use literal notation, e.g. this.style.fontSize, or you can also use the CSS dashed style using brackets notation, this.style["font-size"].
Just for completeness, if you want the information whether it comes from the style attribute or a stylesheet, jQuery's CSS function does just that:
var color = $(this).css("color");
From your comment:
thanks, but if I want all properties can I use this.style ??
If you want all of the inline-styles as text, either get the style attribute (as you're doing) or use this.style.cssText.
If you want all of the styles, regardless of whether they're inline or not, as an object, use getComputedStyle (or currentStyle on obsolete browsers like IE8):
var style = window.getComputedStyle ? getComputedStyle(this) : this.currentStyle;
if (style) { // This will be true on major browsers
    var color = style.color; // Or whatever
}
Examples:
var div = document.querySelector(".foo");
snippet.log("div.style.fontSize: " + div.style.fontSize);
snippet.log("div.style.color: " + div.style.color);
snippet.log("div.style.cssText: " + div.style.cssText);
snippet.log("$(div).attr('style'): " + $(div).attr('style'));
snippet.log("$(div).css('fontSize'): " + $(div).css('fontSize') + " (note that's in pixels, probably, not pt)");
snippet.log("$(div).css('color'): " + $(div).css('color'));
.foo {
  font-size: 14pt;
  color: green;
}
<div class="foo" style="font-size: 12pt">
  This has an inline <code>font-size: 12pt</code> and
  CSS (not inline) giving <code>font-size: 14pt</code> and <code>color: green</code>.
</div>
<hr>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<!-- Script provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 -->
<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>
 
 
 
        
        
This is a test2
– luke9999 Oct 02 '15 at 10:00