set value to dropdwon using jquery code example
Example 1: change value of drop down using jquery
$('#ddlID').val('New_OptionValue').change()
Example 2: set dropdown in jquery
$('select[name^="salesrep"] option:selected').attr("selected",null);
$('#ddlID').val('New_OptionValue').change()
$('select[name^="salesrep"] option:selected').attr("selected",null);