I have a html page with a select element like this:
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width"> <title>JS Bin</title> </head> <body> <select id="ExSelect"> <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> </select> <br> <br> <script src="https://code.jquery.com/jquery-3.1.0.js"></script> <button onclick="ToTheNext()" id="btnext">Next</button> </body> </html>
And I’m using this simple function on the button OnClick to change the selected item to the next option item of the dropdown:
function ToTheNext()
{
$('#ExSelect option:selected').next().attr('selected', 'selected');
}
My question is: How can i change the selected item to the previous option of this tag using Vanilla JavaScript or jQuery?
Jsbin Example: https://jsbin.com/nuyeduf/edit?html,js,output
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Answer
Two problems – first by using attr you’re setting more than one option to selected, which is probably not what you want to do as it will stop the prev() from working as you expect.
Change your code like this:
function ToTheNext()
{
$('#ExSelect option:selected').next().prop('selected', true);
}
function ToThePrevious()
{
$('#ExSelect option:selected').prev().prop('selected', true);
}
https://jsbin.com/xewopobasi/1/edit?html,js,output
If you’re using jQuery then stop using onclick attributes and instead assign click handlers appropriately
$('#btnext').on('click', function(){
$('#ExSelect option:selected').next().prop('selected', true);
});
$(function(){
$('#btnext').on('click',function(){
$('#ExSelect option:selected').next().prop('selected', true);
});
$('#btprev').on('click',function(){
$('#ExSelect option:selected').prev().prop('selected', true);
});
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <select id="ExSelect"> <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> </select> <br> <br> <button id="btnext">Next</button> <button id="btprev">Prev</button>