How to select a value in a select dropdown with JavaScript?

Question

i have a drop down like this

<select style="width: 280px" id="Mobility" name="Mobility">
  <option selected="">Please Select</option>
  <option>K</option>
  <option>1</option>
  <option>2</option>
  <option>3</option>
  <option>4</option>
  <option>5</option>
  <option>6</option>
  <option>7</option>
  <option>8</option>
  <option>9</option>
  <option>10</option>
  <option>11</option>
  <option>12</option>
</select>

I use this line to select a value it works in Mozilla not in IE? Why its not working?

var element = document.getElementById("Mobility");
element.value = "10";

Answer 1

Use the selectedIndex property :

document.getElementById("Mobility").selectedIndex = 12; //Option 10

Alternate method:

Loop through each value:

//Get select object
var objSelect = document.getElementById("Mobility");

//Set selected
setSelectedValue(objSelect, "10");

function setSelectedValue(selectObj, valueToSet) {
    for (var i = 0; i < selectObj.options.length; i++) {
        if (selectObj.options[i].text== valueToSet) {
            selectObj.options[i].selected = true;
            return;
        }
    }
}

Answer 2

easiest way is to just use this

document.getElementById("mySelect").value = "banana";

myselect is name of your dropdown banana is just one of items in your dropdown list

Answer 3

function setSelectedIndex(s, v) {
    for ( var i = 0; i < s.options.length; i++ ) {
        if ( s.options[i].value == v ) {
            s.options[i].selected = true;
            return;
        }
    }
}

Where s is the dropdown and v is the value

Answer 4

如果您知道价值，最简单的可能解决方案

document.querySelector('option[value=" + value +"]').selected = true

Answer 5

I realize that this is an old question, but I'll post the solution for my use case, in case others run into the same situation I did when implementing James Hill's answer (above) .

I found this question while trying to solve the same issue. James' answer got me 90% there. However, for my use case, selecting the item from the dropdown also triggered an action on the page from dropdown's onchange event. James' code as written did not trigger this event (at least in Firefox, which I was testing in). As a result, I made the following minor change:

function setSelectedValue(object, value) {
    for (var i = 0; i < object.options.length; i++) {
        if (object.options[i].text === value) {
            object.options[i].selected = true;
            object.onchange();
            return;
        }
    }

    // Throw exception if option `value` not found.
    var tag = object.nodeName;
    var str = "Option '" + value + "' not found";

    if (object.id != '') {
        str = str + " in //" + object.nodeName.toLowerCase()
              + "[@id='" + object.id + "']."
    }

    else if (object.name != '') {
        str = str + " in //" + object.nodeName.toLowerCase()
              + "[@name='" + object.name + "']."
    }

    else {
        str += "."
    }

    throw str;
}

Note the object.onchange() call, which I added to the original solution . This calls the handler to make certain that the action on the page occurs.

Edit

Added code to throw an exception if option value is not found; this is needed for my use case.

Answer 6

Using Javascript:

document.getElementById('drpSelectSourceLibrary').value = 'Seven';

Using Jquery:

$('select').prop('selectedIndex', 3); // This will select the 4th option from the dropdown list

Answer 7

这可以做到

document.forms['someform'].elements['someelement'].value

Answer 8

Using some ES6:

Get the options first, filter the value based on the option and set the selected attribute to true.

 window.onload = () => { [...document.querySelector(`#Mobility`).options] .filter(x => x.value === "12")[0] .setAttribute('selected', true); };

 <select style="width: 280px" id="Mobility" name="Mobility"> <option selected disabled>Please Select</option> <option>K</option> <option>1</option> <option>2</option> <option>3</option> <option>4</option> <option>5</option> <option>6</option> <option>7</option> <option>8</option> <option>9</option> <option>10</option> <option>11</option> <option>12</option> </select>

Answer 9

Instead of doing

function setSelectedIndex(s, v) {
    for ( var i = 0; i < s.options.length; i++ ) {
        if ( s.options[i].value == v ) {
            s.options[i].selected = true;
            return;
        }
    }
}

I solved this problem by doing this

function setSelectedValue(dropDownList, valueToSet) {
    var option = dropDownList.firstChild;
    for (var i = 0; i < dropDownList.length; i++) {
        if (option.text.trim().toLowerCase() == valueToSet.trim().toLowerCase()) {
            option.selected = true;
            return;
        }
        option = option.nextElementSibling;
    }
}

If you work with strings, you should use the .trim() method, sometimes blank spaces can cause trouble and they are hard to detect in javascript debugging sessions.

dropDownList.firstChild will actually be your first option tag. Then, by doing option.nextElementSibling you can go to the next option tag, so the next choice in your dropdownlist element. If you want to get the number of option tags you can use dropDownList.length which I used in the for loop.

Hope this helps someone.

Answer 10

Yes. As mentioned in the posts, value property is nonstandard and does not work with IE. You will need to use the selectedIndex property to achieve this. You can refer to the w3schools DOM reference to see the properties of HTML elements. The following link will give you the list of properties you can work with on the select element.

http://www.w3schools.com/jsref/dom_obj_select.asp

Update

This was not supported during 2011 on IE. As commented by finnTheHuman, it is supported at present.

Answer 11

You can solve this With Javascript like:

var newValue = "testing";
document.getElementById('id_Of_the_select_tag').value = value;

Or with Jquery like this:

var newValue = "testing";

$("#id_Of_the_select_tag").val(newValue);

Answer 12

I made two significant improvements to the excellent alternative method, which was much better suited to my requirements, that was included in the accepted answer by @Janes Hill.

1. As written, the code in his answer matches against the display text of the combo box. I needed to match against the string specified in the value attribute of the option tag.

2. To allow for the possibility that the input value is missing from the list, I wanted to return the selectedIndex so that it can be tested, returning an invalid index when that happens.

3. As a matter of practice, I usually make all such evaluations case insensitive.

My improved function follows.

 function SetSelectedValue ( selectObj, valueToSet ) { const value2SetLC = valueToSet.toLowerCase(); for ( var i = 0; i < selectObj.options.length; i++ ) { if ( selectObj.options [ i ].value.toLowerCase ( ) === value2SetLC ) { selectObj.options [ i ].selected = true; return i; } // if ( selectObj.options [ i ].value.toLowerCase ( ) === value2SetLC ) } // for ( var i = 0; i < selectObj.options.length; i++ ) return -1; // Value not found } // function SetSelectedValue