Is HTML text string within current scrolling visible area of browser window?

[Keith Clarke]

Hi Jim,
Thanks for the response and the pointers. Good to know that some discovery can be achieved algorithmically - my dream is still alive!

Thanks also for the specific pointers - more for the research list.
Best,
Keith..  
 
On 27 Mar 2011, at 14:29, Jim Ault wrote:

> 
> On Mar 27, 2011, at 3:55 AM, Keith Clarke wrote:
> 
>> Hi folks,
>> Can anyone help me with the correct terms to seed my Google search?
>> 
>> I'm trying to discover whether it's possible to check programmatically (maybe with Javascript, Jquery, etc.) whether a specific element on a web page (that is readable from the page HTML), such as a specific div, tag or string, is currently within the visible rendered page area of a browser window with a (vertical) scroll bar.
>> 
>> Otherwise, if it's a specific page - with a known layout and therefore calculable coordinates for the element to find - is it possible to know how the browser window's current size and scroll offset relate to the 'underlying' page?
> 
> 
> 
> This calculation is the same for all browsers, except that
> IE does not follow the same metrics calculations, and, of course, it is different with in versions of IE.
> 
> 
> offsetLeft & offsetTop < HTML DOM
> http://www.w3schools.com/jsref/dom_obj_all.asp
> 
> pageX & pageY <  window scroll
> http://www.w3schools.com/jsref/prop_win_pagexoffset.asp
> 
> Also, 'position' is the keyword for CSS
> 
> JQuery
> go to  http://visualjquery.com/ (which is a very cool page by Remy Sharp)
> Enter the letter 'O' into the filter box and click on the 'offset' button that appears.
> You will see an example calculation.
> 
> Of course, 'location' refers to the URL of the content, not page layout.
> 
> I just saw a javascript routine that does the calculation based on browser-detection a couple days ago, but can't remember exactly where it is.  If you need more info, I could try to find it.  Let me know.
> 
> 
> Jim Ault
> Las Vegas
>