How to load a variable name as id or class name to javascript selector? Anybody know better way

Question

X=100;
Var s=['s1', 's2'];
$(s[0]).val(x) ;

Answer 1

Are you trying to copy x to the values of both elements identified by s1 and s2?

If that's what you mean, this will work:
If s1 and s2 are id's:
$('#s1, #s2').val(x);

If s1 and s2 are classes:
$('.s1, .s2').val(x);

jquery selectors can represent any number of elements so val can operate on multiple elements in one call.
The comma in a CSS selector basically means "or" or "union".

The code in your question won't select any elements because s1 isn't a valid tag name.

A couple more minor points about your code are:
- "Var" should be replaced with "var".
- "x" needs to be a consistent case. X and x aren't the same.