UniqueID vs html element actual id

I'm creating composite control, which has two other components that rely on each other.

In component A (image), I access component's B (input) UniqueID which equals

MyTextBox1$BoldTextBox

I use it in onclick JavaScript code...

But in rendered HTML input element has following id

MyTextBox1_BoldTextBox

So my javascript code , generated inside composite control has something like this:

onclick=$('#MyTextBox1开发者_Python百科$BoldTextBox').....

instead of:

onclick=$('#MyTextBox1_BoldTextBox').....

Could somebody please explain what is happening, and how can I reliably associate those two controls ?

Thanks , Paweł

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You want the ClientID property instead of the UniqueID property.

The reason for this is (sort of) explained on Atanas Korchev's blog post "The difference between Id, ClientID, and UniqueID".