Gets or sets a value that indicates whether scripts are loaded before or after markup for the page UI is loaded.
Assembly: System.Web.Extensions (in System.Web.Extensions.dll)
The property determines how scripts in the Scripts collection are loaded relative to the markup for the page UI.
When the property is true, a script element is rendered before the page's UI markup is loaded. In this scenario, if UI elements are defined in scripts, the UI will be fully functional when it loads. However, if the script accesses UI elements in the markup for which instances have not yet been created, an error might occur. To make sure that UI elements are loaded before you access them, handle the load event of the Sys.Application class.
When the property is false, a script element is rendered after the page's UI markup is rendered. In this scenario, the UI loads more quickly, but it might not be fully functional if scripts that define additional UI elements have not finished loading.