scripts run at the end

Hi.I have 3 scripts which are used for showing the ads.because they are so heavy.I'd like to show and run them at last(after the load page).
I've tried:
if (document.readyState == "complete"){
document.onreadystatechange = myfunctionName;
}

but the problem is after the page load completes it doesnt show me the ads,my scripts are not at the end of the page they are 3 different places in my page.
I really need help.
thanks

 

can you please provide links and/or better examples of what you are doing? thank you