[Plugin: WP-chgFontSize] Doesn't work with tag

i try activating this plugin it works if the resizing text is in the
specific div vlass or id.
eg:- DIV Base Element:content
“<div class=”content”> resizing text </div>”

bt i need to resize the text inside <p> tag in content div.
eg:-
“<div class=”content”> <p> resizing text </p> </div>”

thanks in advance.
im sory im new to wordpress and plugins please help.

http://ww.wp.xz.cn/extend/plugins/wp-chgfontsize/