Can we test the Performance for viewing pages without URLs

Hi, I am new to this. I wanted to know if we could test the performance of an application which opens in a new browser and does not have URls displayed for each page. My application once the URL is typed in it opens in a new browser window which does not have an address bar. So i will not be able to get the address each time. I want to test the performance of a page when I click on a button another page(in the same window) opens up and loads all the data in the page. How can I get the response time ie calculate the time period from the time when i clicked on the button to the time all the information loads... I need to know the steps to do in the Load UI tool. I have not used Soap UI. All i need to do in my application is to click on a button- see whether the next page loads in 15 secs. need to repeat this process only 3 times.. just need 3 tries. but i have around 50 buttons to do. Load UI gives a list of the time which it generates and seems to be more leaning towards number of people loggin in rather than the response time. i might be wrong... please help me!!!
Thanks in Advance.