jquery_notes.js

//Select class selector

//select option by index
$('#frakt_type option:eq(0)').prop("selected",true);

//select option by value
$('#frakt_type option[value="'+4+'"]').prop("selected",true);

//Select option by contains
$('#frakt_type option:contains("find_text")').prop("selected",true);

A match on "Selection 10" might be unwanted. I found no selector to match the full text, but a filter works:
 $('.selDiv option').filter(function(i, e) { return $(e).text() == "Selection 1"})

//Get option value
$('#frakt_type option:selected').val();

//remove option by data index
$('#frakt_type option[data-id="'+4+'"]').remove();

//add options to select
var option = '<option value="'+val+'" data-id="'+frakt_inc+'f">'+text+'</option>';
$("#frakt_type").append(option);

//change data attributes in select
$('#frakt_type option[data-id="'+$id+'"]').data("id",frakt_inc+"f");
$('#frakt_type option[data-id="'+$id+'"]').attr("data-id",frakt_inc+"f");

//Remove All Options Except The First
$('select').children('option:not(:first)').remove();

//Add options from array
$.each(sel_array, function(key, value) {
     $('#mySelect')
         .append($("<option></option>")
         .attr("value",key)
         .text(value));
});

//Check not numeric
if(!$.isNumeric($id)) {
   // do something
}
//Change HTML TEXT
var html = $('#offertHtml').html();
                    var $html = $('<div />',{html:html});
                    $html.find('#box').css({"box-shadow":''});
                    $('#html_offert').text($html.html());
//Ajax method
//use data:{data:data} to send object

$.ajax({
 url: "ajax_file.php",
 type: "post", //or get
 //data: fdata, //(or)
 data: {
  lang: $('#lankade').val()
 },
 //dataType: "json", //only get Json File
 success: function(data)
{
 alert(data);
},
error: function(error)
{
alert(error);
}
});

//prevent event in a form.
$(this).preventDefault();
//Get Ready state
$( document ).ready(function() {
        console.log( "document loaded" );
    });
 
    $( window ).on( "load", function() {
        console.log( "window loaded" );
    });

//Dynamic add event listener
$('#staticDiv').on('click', 'yourSelector', function() {
  //do something
});