当所选下拉选项的值大于0时，使提交按钮处于活动状态

Question

I am trying to get the submit button in my code to display if the user chooses one option from the dropdown menu. I figured I could do this by using the value attribute. Please see my code below, I have included some JavaScript but im aware this could be completely wrong!

<select id="button1" class="button" title="Button 1">
  <option value="0">--Please choose an option for the first blank--</option>
  <option id="buttonText1_1" class="buttonText" value="1">Arsenal</option>
  <option id="buttonText1_2" class="buttonText" value="2">Spurs</option>
  <option id="buttonText1_3" class="buttonText" value="3">Liverpool</option>
  <option id="buttonText1_4" class="buttonText" value="4">Man Utd</option>
  <option id="buttonText1_5" class="buttonText" value="5">Man City</option>
</select>
<div class="break"></div>
<select id="button2" class="button" title="Button 2">
  <option value="0">--Please choose an option for the second blank--</option>
  <option id="buttonText2_1" class="buttonText" value="1">Lampard</option>
  <option id="buttonText2_2" class="buttonText" value="2">Gerrard</option>
  <option id="buttonText2_3" class="buttonText" value="3">Scholes</option>
  <option id="buttonText2_4" class="buttonText" value="4">Viera</option>
  <option id="buttonText2_5" class="buttonText" value="5">Keane</option>
</select>

<div class="break"></div>

<button title="Submit Button" id="submitButton" class="button" onClick="submitClick()">
  <p id="submitText" class="buttonText">Submit</p>
</button>

JS:

    document.getElementById("button1").onchange = function() {
      if(this.value != 0) {
        optionVal++;
      }
    }
    document.getElementById("button2").onchange = function() {
      if(this.value != 0) {
        optionVal++;
      }
    }

    function activateSub() {
      $('#submitButton').css('display', 'block');
    }

    function doSomething() {
      if(optionVal != 0) {
       activateSub();
      }
    }

I have made a JSFiddle with this code in. Thank you in advance!

Answer 1

Using jQuery :

$('select').on('change', function() {
    // shows the button if even one select has selected option
    $btn = $('#submitButton');
    $btn.hide();
    $('select').each(function() {
        if ($(this).val() != 0) {
            $btn.show();
            return false;
        }
    });
 });

I've forked your Fiddle

Answer 2

If you want to show the button only if both selects have a value > "0" you can check is this way:

VanillaJS:

function submitVisiblity() {
     // If you use numeric value into options' "value" attribute you should convert (parse) the option value from a string to an integer
     if (parseInt(document.getElementById("button1").value) > 0 &&

         parseInt(document.getElementById("button2").value) > 0) {
         document.getElementById('submitButton').style.display = 'block'
     } else {
         document.getElementById('submitButton').style.display = 'none'
     }
 }


 document.getElementById("button1").onchange = submitVisiblity
 document.getElementById("button2").onchange = submitVisiblity

JQuery:

$("#button1,#button2").on('change',function() {
  if (parseInt($("#button1").val()) > 0 && parseInt($("#button2").val()) > 0) {
    $('#submitButton').show()
  } else {
    $('#submitButton').hide()
  }
});

---

Bye :)