Find ASP.Net Controls without using ClientID Tags in Javascript

Hi 

In my website i have some users these users have their own page that they can put their product on it.

their page name is Store.aspx 

and i have users table i want my users insert their keyword in DB  after that thier keyword fetch to meta tag i want all my users have differrent mete tag in their page how i can do it ?i try it with this code

this is my users table

string[] keywords = { "KeyWord_1", "KeyWord_2", "KeyWord_3" };

HtmlMeta htmlMeta;

foreach (string keyword in keywords)

{
       htmlMeta = new HtmlMeta();
       htmlMeta.HttpEquiv = "keywords";
       htmlMeta.Content = keyword;
       this.Page.Header.Controls.Add(htmlMeta);

}

but this error occur

The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>).

is there any code in JQUERY that i do it?

thanks