Changing HTML element using variable

[slj90]

Usually it would be something like:

 $("#lblpasswordmessage").html("Password is too short"); 

But how do you do it using a variable? For example say the variable is called 'pwm';

 $("#pwm").html("Password is too short"); 
 $("pwm").html("Password is too short"); 
 $(pwm).html("Password is too short"); 

Thanks

[requinix]

The third, if pwm contains "#lblpasswordmessage". Or if it doesn't include the hash sign then

$("#" + pwm)