Form Select Change Dynamic List Option Elements Tutorial

Learn how to program dynamic select form list elements. To demonstrate the logic we will show how to change options of a select list based on the selection the user makes from the first list. A web application developer will definitely need to know how to do this when they get into form programming that involves data intake of categories and subcategories from a user. <!DOCTYPE html> <html> <head> <script> function populate(s1,s2){ var s1 = document.getElementById(s1); var s2 = document.getElementById(s2); s2.innerHTML = ""; if(s1.value == "Chevy"){ var optionArray = ["|","camaro|Camaro","corvette|Corvette","impala|Impala"]; } else if(s1.value == "Dodge"){ var optionArray = ["|","avenger|Avenger","challenger|Challenger","charger|Charger"]; } else if(s1.value == "Ford"){ var optionArray = ["|","mustang|Mustang","shelby|Shelby"]; } for(var option in optionArray){ var pair = optionArray[option].split("|"); var newOption = document.createElement("option"); newOption.value = pair[0]; newOption.innerHTML = pair[1]; s2.options.add(newOption); } } </script> </head> <body> <h2>Choose Your Car</h2> <hr /> Choose Car Make: <select id="slct1" name="slct1" onchange="populate(,'slct2')"> <option value=""></option> <option value="Chevy">Chevy</option> <option value="Dodge">Dodge</option> <option value="Ford">Ford</option> </select> <hr /> Choose Car Model: <select id="slct2" name="slct2"></select> <hr /> </body> </html>