选择特定选择时如何运行javascript function？

Question

I am thinking of running a javascript function when selecting a specific selection, such as:

<select name="fruit">
<option value="1">orange</option>
<option value="2">apple</option>
<option value="3">banana</option>
</select>

And if I select "orange", a orange picture will pop out like:

function department() {
    let form = document.basic;
    let choice = form.fruit.value;
    if (choice === 1) {
        document.getElementById("orange_img").style.display = "inherit";
    }
}

How can I get this javascript work?

PS: Is there methods without jquery?

Answer 1

You can add eventListener to onchange event, check the value, and add custom logic to handle it. No need of jquery!

 const fruitSelect = document.getElementById('fruit'); fruitSelect.addEventListener('change', (e) => { const value = e.target.value; if(value === '1') { // corresponds to orange // do stuff here } });

 <select name="fruit" id="fruit"> <option value="1">orange</option> <option value="2">apple</option> <option value="3">banana</option> </select>

Answer 2

Store the links to the images in an object, and then when your option changes update the element with it.

 // List of images const images = { orange: 'https://dummyimage.com/100x100/ffa600/000.png', apple: 'https://dummyimage.com/100x100/2e8b56/000.png', banana: 'https://dummyimage.com/100x100/FFFF00/000.png' }; // Cache the elements const select = document.querySelector('select'); const div = document.querySelector('div'); // Add an event listener to the select select.addEventListener('change', handleChange, false); // Update the background image of the div // with the new image function handleChange() { const img = `url(${images[this.value]})`; div.style.backgroundImage = img; }

 div { height: 100px; width: 100px; }

 <select> <option disabled selected>Choose a colour</option> <option value="orange">orange</option> <option value="apple">apple</option> <option value="banana">banana</option> </select> <div></div>

Answer 3

simply add an onChange event and inside the onChange you can invoke any js function. eg: <select onchange="myFunction()">

Answer 4

Use addEventListener

// Add id to select
<select name="fruit" id="fruit">
<option value="1">orange</option>
<option value="2">apple</option>
<option value="3">banana</option>
</select>

// Add event listener to select
const el = document.getElementById("fruit");
el.addEventListener("change", function() {...});

Answer 5

One approach

 const orange = document.getElementById("orange") apple = document.getElementById("apple") banana = document.getElementById("banana"); orange.addEventListener('click', () => showPopUp('orange')) apple.addEventListener('click', () => showPopUp('apple')) banana.addEventListener('click', () => showPopUp('banana')) function showPopUp(fruit){ alert(fruit) // <--- do something with the fruit }

 <select name="fruit"> <option value="1" id="orange">orange</option> <option value="2" id="apple">apple</option> <option value="3" id="banana">banana</option> </select>

Answer 6

Without jQuery you can do something like this:

const fruitSelect = document.basic.fruit;
fruitSelect.addEventListener('change', (event) => {
    department();
});

I'm assuming form's name is "basic" (inferred from your code).

https://jsfiddle.net/ahvftgL7/

Answer 7

In your html file, // Use ID to make the select container unique

<select name="fruit" id="selectedFruit"  onchange="onChangeFruit()">
<option value="1">orange</option>
<option value="2">apple</option>
<option value="3">banana</option>
</select>

In your js file, you can invoke the function onChangeFruit(),

function onChangeFruit() {
  console.log(document.getElementById("selectedFruit").value);
}