django - Concatenate HTML String -

i want concatenate html string. i'm building modifiable url (not page, internal api).

i'm using django [if helps]

urldata = "http://www.twitch.tv/widgets/live_embed_player.swf?channel=" + {{specificmedia.channel}} 

i'm trying add first section string "{{specificmedia.channel}}" string. , set object variable

<object type="application/x-shockwave-flash"       data= urldata 

is possible without using javascript?

if have use javascript, how access javascript string variable outside of script?

thanks

revised question so, know not possible in html, want simulate html string. how do in java script?

i want make: data = 'somerandomstring'

could like?

<script> var z = 'somerandomstring'; </script>  data = <script type = "text/javascript">document.write(x); </script> 

no, have use javascript. html markup language , cannot calculations. (eg. string1 + string2). second question, i'm not sure.