I am using a jQuery placeholder plugin(https://github.com/danielstocks/jQuery-Placeholder). I need to change the placeholder text with the change in dropdown menu. But it is
simply you can use
$("#yourtextboxid").attr("placeholder", "variable");
where, if variable is string then you can use like above, if it is variable replace it with the name like "variable" with out double quotes.
eg: $("#youtextboxid").attr("placeholder", variable); it will work.
$("#youtextboxid").attr("placeholder", variable);