I want to create a command from the option and go to javascript then display it in the input box.
<select id="change"> <option>Cat</option> <option>Dog</option> <option>Fish</option> </select> <script type="text/javascript"> show('Cat'); </script> <input/> when I choose one of the options, then the contents automatically in the javascript changed. and the reload function runs then displays the result in the input box.
You can try adjusting to your best needs from this snippet
<select id="change"> <option>Cat</option> <option>Dog</option> <option>Fish</option> </select> <script type="text/javascript"> document.getElementById('change').addEventListener('change', function(e) { document.getElementsByTagName('input')[0].value = e.target.value; }); </script> <input/> If you want to call show with selected value you can have
document.getElementById('change').addEventListener('change', function(e) { var selected = e.target.value; show(selected); }); 
show('xxValueFromOptionxx'); code
document.getElementsByTagName('input')[0].value = e.target.value; with show(e.target.value);Try this.
function a(select) { var input = document.getElementById("input"); if (select.value !== "Select option") { input.value = select.value; } else { input.value="" } }<select id="change" onchange="a(this)"> <option>Select option</option> <option>Cat</option> <option>Dog</option> <option>Fish</option> </select> <input id="input" />Hm not sure what your are trying to achieve but this works if your use a normal browser:
//Targets select = document.getElementById("change"); print = document.getElementById("value"); //Function print option printOption = function(loc, option) { loc.innerHTML = option; } //Function force value optionPicker = function(option) { select.value = option; printOption(print, option); }; //Change Listener document.addEventListener("change", function(e){ if(e.target.id === "change") printOption(print, e.target.value); }, false); //Commands optionPicker("Dog");<select id="change"> <option>Cat</option> <option>Dog</option> <option>Fish</option> </select> <div id="value"></div>