RegisterClientScriptBlock parameters usages in real scenarios?

Question

http://i.stack.imgur.com/dVjHt.jpg

I never understood the real usage of the Control , type,key usages of this class.

In general Ive always used with : this , GetType() , "xx"

but now I truly want to understand .

---

msdn :

Control : " the control that is registering the client script"

so...? what difference does it makes who registered it ? the script will be in the head of the page...

Type: "the type of the client script block"

type ??? its javascript. why does he want another type from me ?

Key: "a unique indentifier"

That I can understand - for cases which later to remove... but I'd love for some more advanced explanations

Can I have please , a real life scenario in which I TRULY have to play with those params ?

Answer 1

the most important part is Control which control in html tags you want to register the script for example if you have user control and you want to run the script just for that use this line

ScriptManager.RegisterStartupScript(this, this.GetType(), "alertscript", "document.getElementById('userControl_h1TAG')", true); 

but when you want to register the block and script to all part of that page use this line in CS code of user-control :

ScriptManager.RegisterStartupScript(this.Page, this.Page.GetType(), "alertscript", "document.getElementById('page_h1TAG')", true);