改变<select>javascript的动态选项

Question

Can I use a javascript if/else function to change the select options of a form? I don't want to use CSS to hide/display different dropdown menus, so here is what I've ccome up with:

 function getType() { var x = document.getElementById("food").value; var items; if (x === "fruit") { items = "Apple" || items = "Oranges" || items = "Bananas"; else { items = "Eggplants" || items = "Olives" } document.getElementById("pickone").value; }

 <input type="text" id="food"> <select id="pickone"> <option id="1"></option> <option id="2"></option> </select>

I can't seem to find any documentation about how to do this, so any help would be great.

Answer 1

Can I use a javascript if/else function to change the select options of a form? I don't want to use CSS to hide/display different dropdown menus, so here is what I've ccome up with:

 function getType() { var x = document.getElementById("food").value; var items; if (x === "fruit") { items = "Apple" || items = "Oranges" || items = "Bananas"; else { items = "Eggplants" || items = "Olives" } document.getElementById("pickone").value; }

 <input type="text" id="food"> <select id="pickone"> <option id="1"></option> <option id="2"></option> </select>

I can't seem to find any documentation about how to do this, so any help would be great.

Answer 2

Can I use a javascript if/else function to change the select options of a form? I don't want to use CSS to hide/display different dropdown menus, so here is what I've ccome up with:

 function getType() { var x = document.getElementById("food").value; var items; if (x === "fruit") { items = "Apple" || items = "Oranges" || items = "Bananas"; else { items = "Eggplants" || items = "Olives" } document.getElementById("pickone").value; }

 <input type="text" id="food"> <select id="pickone"> <option id="1"></option> <option id="2"></option> </select>

I can't seem to find any documentation about how to do this, so any help would be great.

Answer 3

Can I use a javascript if/else function to change the select options of a form? I don't want to use CSS to hide/display different dropdown menus, so here is what I've ccome up with:

 function getType() { var x = document.getElementById("food").value; var items; if (x === "fruit") { items = "Apple" || items = "Oranges" || items = "Bananas"; else { items = "Eggplants" || items = "Olives" } document.getElementById("pickone").value; }

 <input type="text" id="food"> <select id="pickone"> <option id="1"></option> <option id="2"></option> </select>

I can't seem to find any documentation about how to do this, so any help would be great.