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javascriptdrop-down-menudropdownhtml-select

How to check if a selected option is of higher value than one from another dropdown?

So I have these two dropdown lists in html that look like this :

<SELECT name="obj_1" size="1" class="archive-select">
        <OPTION selected disabled>from</OPTION>
        <OPTION value="1">Less than 200</OPTION>
        <OPTION value="200">200</OPTION>
        <OPTION value="400">400</OPTION>
        <OPTION value="600">600</OPTION>
        <OPTION value="800">800</OPTION>
        <OPTION value="1000">1'000</OPTION>
        <OPTION value="1200">1'200</OPTION>
        <OPTION value="1400">1'400</OPTION>
        <OPTION value="1600">1'600</OPTION>
        <OPTION value="1800">1'800</OPTION>
        <OPTION value="2000">2'000</OPTION>
        <OPTION value="2200">2'200</OPTION>
        <OPTION value="2400">2'400</OPTION>
        <OPTION value="2600">2'600</OPTION>
        <OPTION value="2800">2'800</OPTION>
        <OPTION value="3000">3'000</OPTION>
    </SELECT><br>
    <SELECT name="obj_2" size="1" style="margin-bottom:15px;" class="archive-select">
        <OPTION selected disabled>to</OPTION>
        <OPTION value="200">200</OPTION>
        <OPTION value="400">400</OPTION>
        <OPTION value="600">600</OPTION>
        <OPTION value="800">800</OPTION>
        <OPTION value="1000">1'000</OPTION>
        <OPTION value="1200">1'200</OPTION>
        <OPTION value="1400">1'400</OPTION>
        <OPTION value="1600">1'600</OPTION>
        <OPTION value="1800">1'800</OPTION>
        <OPTION value="2000">2'000</OPTION>
        <OPTION value="2200">2'200</OPTION>
        <OPTION value="2400">2'400</OPTION>
        <OPTION value="2600">2'600</OPTION>
        <OPTION value="2800">2'800</OPTION>
        <OPTION value="3000">3'000</OPTION>
        <OPTION value="300000">More than 3'000</OPTION>
    </SELECT>

What I would like to do, is when the user selects in the first dropdown a certain number, to disable the ones that are of lower value in the second dropdown list. For example if I select 400, the options "Less than 200" and "200" should be disabled in the dropdown.

I kind of have the idea on how to work around this, but I just don't really know how I can check what the user chose and do my tests based on that. Any help is appreciated !

Solution

  • Try like this:

    var obj_1 = document.querySelector('select[name="obj_1"]');
var obj_2_options = document.querySelectorAll('select[name="obj_2"] option');

obj_1.onchange = function() {
  var val_1 = parseInt(obj_1.value.replace("'", ""));

  for (var i = 0; i < obj_2_options.length; i++) {
    var val_2 = parseInt(obj_2_options[i].value.replace("'", ""));
    obj_2_options[i].disabled = (val_2 < val_1);
  }
}
    <SELECT name="obj_1" size="1" class="archive-select">
  <OPTION selected disabled>from</OPTION>
  <OPTION value="1">Less than 200</OPTION>
  <OPTION value="200">200</OPTION>
  <OPTION value="400">400</OPTION>
  <OPTION value="600">600</OPTION>
  <OPTION value="800">800</OPTION>
  <OPTION value="1000">1'000</OPTION>
  <OPTION value="1200">1'200</OPTION>
  <OPTION value="1400">1'400</OPTION>
  <OPTION value="1600">1'600</OPTION>
  <OPTION value="1800">1'800</OPTION>
  <OPTION value="2000">2'000</OPTION>
  <OPTION value="2200">2'200</OPTION>
  <OPTION value="2400">2'400</OPTION>
  <OPTION value="2600">2'600</OPTION>
  <OPTION value="2800">2'800</OPTION>
  <OPTION value="3000">3'000</OPTION>
</SELECT><br>
<SELECT name="obj_2" size="1" style="margin-bottom:15px;" class="archive-select">
  <OPTION selected disabled>to</OPTION>
  <OPTION value="200">200</OPTION>
  <OPTION value="400">400</OPTION>
  <OPTION value="600">600</OPTION>
  <OPTION value="800">800</OPTION>
  <OPTION value="1000">1'000</OPTION>
  <OPTION value="1200">1'200</OPTION>
  <OPTION value="1400">1'400</OPTION>
  <OPTION value="1600">1'600</OPTION>
  <OPTION value="1800">1'800</OPTION>
  <OPTION value="2000">2'000</OPTION>
  <OPTION value="2200">2'200</OPTION>
  <OPTION value="2400">2'400</OPTION>
  <OPTION value="2600">2'600</OPTION>
  <OPTION value="2800">2'800</OPTION>
  <OPTION value="3000">3'000</OPTION>
  <OPTION value="300000">More than 3'000</OPTION>
</SELECT>

    By looping through the option values for obj_2, you can compare them to the value of obj_1 and disable them accordingly.

    EDIT: In jQuery this would be:

    var obj_1 = $('select[name="obj_1"]');
var obj_2_options = $('select[name="obj_2"] option');

obj_1.on('change', function() {
  var val_1 = parseInt(obj_1.val().replace("'", ""));
  
  obj_2_options.each(function() {
    var val_2 = parseInt($(this).val().replace("'", ""));
    $(this).attr('disabled', (val_2 < val_1));
  });
});
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<SELECT name="obj_1" size="1" class="archive-select">
  <OPTION selected disabled>from</OPTION>
  <OPTION value="1">Less than 200</OPTION>
  <OPTION value="200">200</OPTION>
  <OPTION value="400">400</OPTION>
  <OPTION value="600">600</OPTION>
  <OPTION value="800">800</OPTION>
  <OPTION value="1000">1'000</OPTION>
  <OPTION value="1200">1'200</OPTION>
  <OPTION value="1400">1'400</OPTION>
  <OPTION value="1600">1'600</OPTION>
  <OPTION value="1800">1'800</OPTION>
  <OPTION value="2000">2'000</OPTION>
  <OPTION value="2200">2'200</OPTION>
  <OPTION value="2400">2'400</OPTION>
  <OPTION value="2600">2'600</OPTION>
  <OPTION value="2800">2'800</OPTION>
  <OPTION value="3000">3'000</OPTION>
</SELECT><br>
<SELECT name="obj_2" size="1" style="margin-bottom:15px;" class="archive-select">
  <OPTION selected disabled>to</OPTION>
  <OPTION value="200">200</OPTION>
  <OPTION value="400">400</OPTION>
  <OPTION value="600">600</OPTION>
  <OPTION value="800">800</OPTION>
  <OPTION value="1000">1'000</OPTION>
  <OPTION value="1200">1'200</OPTION>
  <OPTION value="1400">1'400</OPTION>
  <OPTION value="1600">1'600</OPTION>
  <OPTION value="1800">1'800</OPTION>
  <OPTION value="2000">2'000</OPTION>
  <OPTION value="2200">2'200</OPTION>
  <OPTION value="2400">2'400</OPTION>
  <OPTION value="2600">2'600</OPTION>
  <OPTION value="2800">2'800</OPTION>
  <OPTION value="3000">3'000</OPTION>
  <OPTION value="300000">More than 3'000</OPTION>
</SELECT>