Adding option in select based on current options

Question

I have a function that loops through data and dynamically creates options inside a select. The problem is I only want one "please select" option to show up, not one for each time the loop runs. So basically, if this option already exists don't add it again. I tried this code but it will not work, it doesn't show this option at all.

if ($("#level"+num+" option[value = 'base']").length < 0) {
    $("#level"+num ).prepend($("<option></option>")
                    .attr("value", "base")//.id )
                    .text( "Please select an option" ) 
     );
};

Answer 1

Length will never be < 0. It will be 0 or greater...

if ($("#level"+num+" option[value = 'base']").length == 0) {
    $("#level"+num ).prepend($("<option></option>")
                .attr("value", "base")//.id )
                .text( "Please select an option" ) 
    );
};