Browser based web conferencing employing layering to display screen updates

Abstract

A browser based web conferencing method is disclosed, wherein Hypertext Markup Language (HTML) code is transmitted to a browser of an attendee computer. A first screen update request is transmitted over a network, and HTML code is received identifying a screen update image of a first layer. A request to receive the screen update image of the first layer is transmitted over the network, and the screen update image of the first layer is displayed. A second screen update request is transmitted over a network, and HTML code is received identifying a screen update image of a second layer. A request to receive the screen update image of the second layer is transmitted over the network, and the screen update image of the second layer is displayed, wherein the screen update image of the second layer overlaps the screen update image of the first layer.

1 . A browser based web conferencing method, the method comprising transmitting Hypertext Markup Language (HTML) code to a browser of an attendee computer connected to a network, the HTML code comprising code segments for:
 transmitting over the network a first screen update request;   receiving over the network HTML code identifying a screen update image of a first layer;   transmitting over the network a request to receive the screen update image of the first layer;   displaying the screen update image of the first layer;   transmitting over the network a second screen update request;   receiving over the network HTML code identifying a screen update image of a second layer;   transmitting over the network a request to receive the screen update image of the second layer; and   receiving and displaying the screen update image of the second layer,   wherein the screen update image of the second layer overlaps at least part of the screen update image of the first layer.   
   
   
       2 . The method as recited in  claim 1 , wherein the HTML code comprises an img HTML tag. 
   
   
       3 . The method as recited in  claim 1 , wherein the HTML code identifying the screen update image of the first layer comprises a first z-index HTML tag and the HTML code identifying the screen update image of the second layer comprises a second z-index HTML tag. 
   
   
       4 . The method as recited in  claim 1 , wherein:
 the first update image of the first layer represents a substantially full screen update; and   the second update image of the second layer represents a partial screen update.   
   
   
       5 . The method as recited in  claim 1 , wherein the HTML code further comprises code segments for:
 storing the HTML code of the first layer in an HTML element; and   appending the HTML code of the second layer to the HTML element.   
   
   
       6 . The method as recited in  claim 5 , wherein the HTML code further comprises a code segment for deleting the HTML code from the HTML element when a full screen update image is received. 
   
   
       7 . The method as recited in  claim 1 , wherein the code segment for transmitting over the network the screen update request comprises a request-update script. 
   
   
       8 . The method as recited in  claim 7 , wherein:
 the code segment for receiving the HTML code of the first layer comprises a code segment for receiving HTML code identifying a plurality of screen update images of the first layer; and   the code segment for transmitting over the network a request to receive the screen update image of the first layer comprises an image-load script executed in connection with receiving one of the screen update images, wherein the image-load script executes the request-update script after all of the screen update images of the first layer have been displayed.   
   
   
       9 . The method as recited in  claim 1 , wherein the HTML code further comprises code segments for:
 detecting a communication error by a timeout period when a browser has not received any images; and   transmitting over the network a request for a full screen update image in response to the communication error.   
   
   
       10 . A computer readable medium comprising code segments to be executed by a computer, the code segments for:
 transmitting over a network a first screen update request;   receiving over the network Hypertext Markup Language (HTML) code identifying a screen update image of a first layer;   transmitting over the network a request to receive the screen update image of the first layer;   displaying the screen update image of the first layer;   transmitting over the network a second screen update request;   receiving over the network HTML code identifying a screen update image of a second layer;   transmitting over the network a request to receive the screen update image of the second layer; and   receiving and displaying the screen update image of the second layer,   wherein the screen update image of the second layer overlaps at least part of the screen update image of the first layer.   
   
   
       11 . The computer readable medium as recited in  claim 10 , wherein the HTML code comprises an img HTML tag. 
   
   
       12 . The computer readable medium as recited in  claim 10 , wherein the HTML code identifying the screen update image of the first layer comprises a first z-index HTML tag and the HTML code identifying the screen update image of the second layer comprises a second z-index HTML tag. 
   
   
       13 . The computer readable medium as recited in  claim 10 , wherein:
 the first update image of the first layer represents a substantially full screen update; and   the second update image of the second layer represents a partial screen update.   
   
   
       14 . The computer readable medium as recited in  claim 10 , further comprising code segments for:
 storing the HTML code of the first layer in an HTML element; and   appending the HTML code of the second layer to the HTML element.   
   
   
       15 . The computer readable medium as recited in  claim 14 , further comprising a code segment for deleting the HTML code from the HTML element when a full screen update image is received. 
   
   
       16 . The computer readable medium as recited in  claim 10 , wherein the code segment for transmitting over the network the screen update request comprises a request-update script. 
   
   
       17 . The computer readable medium as recited in  claim 16 , wherein:
 the code segment for receiving the HTML code of the first layer comprises a code segment for receiving HTML code identifying a plurality of screen update images of the first layer; and   the code segment for transmitting over the network a request to receive the screen update image of the first layer comprises an image-load script executed in connection with displaying one of the screen update images, wherein the image-load script executes the request-update script after all of the screen update images of the first layer have been displayed.   
   
   
       18 . The computer readable medium as recited in  claim 10 , further comprising code segments for:
 detecting a communication error; and   transmitting over the network a request for a full screen update image in response to the communication error.   
   
   
       19 . A browser based web conferencing method comprising:
 an attendee computer transmitting over a network a first screen update request;   the attendee computer receiving over the network Hypertext Markup Language (HTML) code identifying a screen update image of a first layer;   the attendee computer transmitting over the network a request to receive the screen update image of the first layer;   the attendee computer displaying the screen update image of the first layer;   the attendee computer transmitting over the network a second screen update request;   the attendee computer receiving over the network HTML code identifying a screen update image of a second layer;   the attendee computer transmitting over the network a request to receive the screen update image of the second layer; and   the attendee computer displaying the screen update image of the second layer,   wherein the screen update image of the second layer overlaps at least part of the screen update image of the first layer.   
   
   
       20 . A browser based web conferencing system comprising a server computer, a presenter computer, and an attendee computer, wherein
 the server computer for receiving screen update images from the presenter computer and for transmitting the screen update images to the attendee computer;   the attendee computer for transmitting to the server computer a first screen update request;   the attendee computer for receiving from the server computer Hypertext Markup Language (HTML) code identifying a screen update image of a first layer;   the attendee computer for transmitting to the server computer a request to receive the screen update image of the first layer;   the attendee computer for displaying the screen update image of the first layer;   the attendee computer for transmitting to the server computer a second screen update request;   the attendee computer for receiving from the server computer HTML code identifying a screen update image of a second layer;   the attendee computer for transmitting to the server computer a request to receive the screen update image of the second layer; and   the attendee computer for displaying the screen update image of the second layer,   wherein the screen update image of the second layer overlaps at least part of the screen update image of the first layer.