Remove values from select list based on condition

问题

I have the following in the page

<select name="val" size="1" >
<option value="A">Apple</option>
<option value="C">Cars</option>
<option value="H">Honda</option>
<option value="F">Fiat</option>
<option value="I">Indigo</option>                    
</select> 

I would like to remove certain values from my select if certain conditions are true.

E.g

if(frm.product.value=="F"){
  // remove Apple and Cars from the select list
}

How can I do this using javascript

回答1:

Give an id for the select object like this:

<select id="mySelect" name="val" size="1" >
    <option value="A">Apple</option>
    <option value="C">Cars</option>
    <option value="H">Honda</option>
    <option value="F">Fiat</option>
    <option value="I">Indigo</option>                    
</select> 

You can do it in pure JavaScript:

var selectobject = document.getElementById("mySelect");
for (var i=0; i<selectobject.length; i++) {
    if (selectobject.options[i].value == 'A')
        selectobject.remove(i);
}

But - as the other answers suggest - it's a lot easier to use jQuery or some other JS library.

回答2:

Check the JQuery solution here

$("#selectBox option[value='option1']").remove();

回答3:

with pure javascript

var condition = true; // your condition
if(condition) {
    var theSelect = document.getElementById('val');
    var options = theSelect.getElementsByTagName('OPTION');
    for(var i=0; i<options.length; i++) {
        if(options[i].innerHTML == 'Apple' || options[i].innerHTML == 'Cars') {
            theSelect.removeChild(options[i]);
            i--; // options have now less element, then decrease i
        }
    }
}

not tested with IE (if someone can confirm it...)

回答4:

The index I will change as soon as it removes the 1st element. This code will remove values 52-140 from wifi channel combo box

obj = document.getElementById("id");
if (obj)
{
        var l = obj.length;
        for (var i=0; i < l; i++)
        {
            var channel = obj.options[i].value;

            if ( channel >= 52 &&  channel <= 140 )
            {
                obj.remove(i);
                i--;//after remove the length will decrease by 1 
            }
        }
    }

回答5:

As some mentioned the length of the select element decreases when removing an option. If you just want to remove one option this is not an issue but if you intend to remove several options you could get into problems. Some suggested to decrease the index manually when removing an option. In my opinion manually decreasing an index inside a for loop is not a good idea. This is why I would suggest a slightly different for loop where we iterate through all options from behind.

var selectElement = document.getElementById("selectId");

for (var i = selectElement.length - 1; i >= 0; i--){
  if (someCondition) {
    selectElement.remove(i);
  }
}

If you want to remove all options you can do something like this.

var selectElement = document.getElementById("selectId");

while (selectElement.length > 0) {
  selectElement.remove(0);
}

回答6:

If you are using JQuery, it goes as follows:

Give an ID to your SELECT

<select name="val" size="1" id="val">
<option value="A">Apple</option>
<option value="C">Cars</option>
<option value="H">Honda</option>
<option value="F">Fiat</option>
<option value="I">Indigo</option>                    
</select>

$("#val option[value='A'],#val option[value='C']").remove();

回答7:

if(frm.product.value=="F"){
    var select = document.getElementsByName('val')[0];
    select.remove(0);
    select.remove(1);
}

回答8:

You may use:

if ( frm.product.value=="F" ){
    var $select_box = $('[name=val]');
    $select_box.find('[value=A],[value=C]').remove(); 
}

Update: If you modify your select box a bit to this

<select name="val" size="1" >
  <option id="A" value="A">Apple</option>
  <option id="C" value="C">Cars</option>
  <option id="H" value="H">Honda</option>
  <option id="F" value="F">Fiat</option>
  <option id="I" value="I">Indigo</option>                    
</select> 

the non-jQuery solution would be this

if ( frm.product.value=="F" ){
    var elem = document.getElementById('A');
    elem.parentNode.removeChild(elem);
    var elem = document.getElementById('C');
    elem.parentNode.removeChild(elem);
}

回答9:

This should do it

document.getElementsByName("val")[0].remove(0);
document.getElementsByName("val")[0].remove(0);

Check the fiddle here

回答10:

You have to go to its parent and remove it from there in javascript.

"Javascript won't let an element commit suicide, but it does permit infanticide"..:)

try this,

 var element=document.getElementsByName(val))
 element.parentNode.removeChild(element.options[0]); // to remove first option

回答11:

Alternatively you can also accomplish this with getElementsByName

<select id="mySelect" name="val" size="1" >
<option value="A">Apple</option>
<option value="C">Cars</option>
<option value="H">Honda</option>
<option value="F">Fiat</option>
<option value="I">Indigo</option>                    
</select> 

So in matching on the option value of "C" we could remove Cars from the list.

var selectobject = document.getElementsByName('val')[0];
for (var i=0; i<selectobject.length; i++){
if (selectobject.options[i].value == 'C' )
    selectobject.remove(i);
  }

回答12:

document.getElementById(this).innerHTML = '';

Put it inside your if-case. What it does is just to check for the current object within the document and replace it with nothing. You'll have too loop through the list first, I am guessing you are already doing that since you have that if.

回答13:

For clear all options en Important en FOR : remove(0) - Important: 0

var select = document.getElementById("element_select");
var length = select.length;
for (i = 0; i < length; i++) {
     select.remove(0);
 //  or
 //  select.options[0] = null;
} 

回答14:

The best answer is this

function f1(){
  var r=document.getElementById('ms');
  for(i=0;i<r.length;i++)
    if(r.options[i].selected==true)
    {
      r.remove(i);
      i--;
    }
}

<select id="ms" size="5" multiple="multiple">
<option>A</option>
<option>B</option>
<option>C</option>
<option>D</option>
<option>E</option>
<option>F</option>
</select>
<input type="button" value="btn1" id="b1" onclick="f1()"/>

Because your visitor can also add custom options as he want and delete them without need any info about his options . This code is the most responsive delete code that you can write as your selected delete..

enjoy it:))))

回答15:

A simple working solution using vanilla JavaScript:

const valuesToRemove = ["value1", "value2"];

valuesToRemove.forEach(value => {
    const mySelect = document.getElementById("my-select");

    const valueIndex = Array.from(mySelect.options).findIndex(option => option.value === value);

    if (valueIndex > 0) {
        mySelect.options.remove(valueIndex);
    }
});

回答16:

To remove options in a select by value I would do (in pure JS) :

document.getElementById('val').options
    .filter(o => o.value === 'A' || o.value === 'C')
    .forEach(o => o.remove());

回答17:

Removing an option

$("#val option[value='A']").remove();

来源：https://stackoverflow.com/questions/62056145/how-to-remove-prefix-according-selected-range-of-number