How can I check whether a option already exist in select by JQuery

Another way using jQuery:

var exists = false; 
$('#yourSelect  option').each(function(){
  if (this.value == yourValue) {
    exists = true;
  }
});

This evaluates to true if it already exists:

$("#yourSelect option[value='yourValue']").length > 0;

if ( $("#your_select_id option[value=<enter_value_here>]").length == 0 ){
  alert("option doesn't exist!");
}

Related