Unable to pass xslt variable in the javascript function

I have added an icon before the image title in asset library. I want to pass the name of the current logged in user and the image title in the JavaScript function to add it in other custom list.

My code for passing the variable:

<xsl:variable name="ImageTitle" select="$thisNode/@Title"/>
<a href="#" onclick="myfunction({$ImageTitle})"> <img src="/add.png" alt="aa" height="10" widht="10"/></a>

JavaScript function:

         function myfunction(title)
     {
        alert(title);
     }

but I am not getting any alert message displaying the title of the image.
What am I missing?