onclick fontsize implementation

Hello all and thank you in advance. I am very unfamiliar with Java and hope someone can help. I have a site using a wordpress theme and want to add the +, -, and reset buttons to control the text size. I am using this site http://www.dyn-web.com/code/fontsize...n.php#examples as my tutorial and am finding out that this is not a step by step buy requires prior knowledge for java coding.


For step one I copied the 3 lines of code and placed them in the header. Then for step 2 I placed them in the single post editor (not sure if the link "#" needs to be changed. And for step 3 I am lost completely. I downloaded the file linked on that page which includes 4 .js files, which I am not even sure if I will need.

Is this something anyone here can help me with?

I am familiar with html and css, and very little php coding, but this is confusing. Thanks.

First off, this is not Java...it is JavaScript. They are two totally separate languages. Many people make this mistake.

As for the implementation, I suggest a much simpler approach!