How to add to a line?

thetext1[0]="Comprehensive JavaScript tutorials and over 400+ free scripts"
thetext1[0]="Second part"

How would I make the second line of that add to the first one?
I tried
.thetext1[0]="second part"
and
+thetext1[0]="second part"

but it wont work :(

thetext1[0]="Comprehensive JavaScript tutorials and over 400+ free scripts"
thetext1[0]+="Second part"

JavaScript uses the plus operator ("+") for concatenation of strings.
http://devedge.netscape.com/library/manuals/2000/javascript/1.5/reference/ops.html#1042582

Hope that helps!

Happy coding! :)