<select id="one" onchange="document.getElementById('two').value=value">
    <option>Select option</option>
    <option >text1</option>
    <option>text2</option>
    <option>text3</option>
</select>
<select id="two" onchange="document.getElementById('one').value=value">
    <option>Select option</option>
    <option>text1</option>
    <option >text2</option>
    <option>text3</option>
</select>

<div class="container">

<select id="one">
    <option>Select option</option>
    <option >text1</option>
    <option>text2</option>
    <option>text3</option>
</select>
<select id="two" >
    <option>Select option</option>
    <option>text1</option>
    <option >text2</option>
    <option>text3</option>
</select>
<select id="three" >
    <option>Select option</option>
    <option>text1</option>
    <option >text2</option>
    <option>text3</option>
</select>

</div>

Array.prototype.map.call(document.querySelectorAll('select'),function(element,index,arr){

    element.addEventListener('change',function(){
        var _value = this.value;
      Array.prototype.map.call(arr,function(e,i,a){
                a[i].value = _value;
            })

    },false)

})