AJAX AlwaysVisible extender control provides the functionality to display the control above all the page content that remains visible whether you scroll the page upwards or downwards. AJAX AlwaysVisible control allows you to fix the position of associated control on the web page that will always appear in front of each control.
Properties of AJAX AlwaysVisible Control
You can learn the use of above properties from the tutorial of AJAX AlwaysVisible control by following the link given at the bottom of this sample.
Try the sample below to understand the functionality of AJAX AlwaysVisible control. Select the position from the Dropdown to set the absolute position of the control. You will see that the targeted control will float over the background content of web page:
AJAX Always Visible Extender Control