Use an attribute value template e.g.
Code:
<a onclick="return toogleMe({bcname}, 'UserName');">...</a>
to meet XSLT syntax requirements.
To meet Javascript syntax requirements, you might need
Code:
<a onclick="return toogleMe('{bcname}', 'UserName');">...</a>
depending on the type of value you want to pass in (i.e. a string).