font size changed on asp.net page

I am using javscript to open a new browser window when a button is clicked.

Here is the script:
Response.Write("<script>window.open('newpage.aspx','_blank','scrollbars=1, resizable=1');</script>");

Interesting thing is with the click of button, the font size changed (increased) in the original asp.net page; refreshing the screen brings back the original font size.
I have a gridview on a different page with a selectable row. When a row is selected, I used javasript to open a new browser window and display selected data details; it has the similar effect of increased font size and upon refreshing screen, I got the original font size.

On the pages, I have font-family:Arial and font-size:10pt

The problem seems to point to the javascript I used; thank you in advance for your help.

I would like to retract the above. Found the problem; has nothing to do with javascript at all.

Can you please tell me what the issue was? I am stuck with the same problem. Thanks for any help.

i am also facing this fontsize incresing problem in asp.net after using the alert().could you tell me the reason and solution for that.