document.getElementById().value average

Question

I have this javascript code in php document:

var product=0;
function add(){
    if (product<10) {
     product++;
    }
    document.getElementById('display').innerHTML = product;
    document.getElementById('display1').value = product;

}
function rem(){
    if (product>1){
     --product;
    }
    document.getElementById('display').innerHTML = product;
    document.getElementById('display1').value = product;

}

var place=0;
function addplace(){
    if (place<10) {
     place++;
    }
    document.getElementById('display_place').innerHTML = place;
    document.getElementById('display_place1').value = place;

}
function remplace(){
    if (place>1){
     --place;
    }
    document.getElementById('display_place').innerHTML = place;
    document.getElementById('display_place1').value = place;

}

Then I have this html code to display vars:

<button style="background-image: url('files/arrow_down.png');" type="button" onClick="rem()"></button>
<button style="background-image: url('files/arrow_up.png');" type="button" onClick="add()"></button>

<div id="display" name="product">
<script type="text/javascript">document.write(product);</script>
</div>/10</div>
<input type="hidden" id="display1" name="display1">

<button style="background-image: url('files/arrow_down.png');" type="button" onClick="remplace()"></button>
<button style="background-image: url('files/arrow_up.png');" type="button" onClick="addplace()"></button>

<div id="display_place">
<script type="text/javascript">document.write(place);</script>
</div>/10</div>
<input type="hidden" id="display_place1" name="display_place1">

So, I display "product" var in "display" div and send the value from "display1" div through form.

Same with "place" var, with "display_place" div and "display_place1".

Now, I need to display this value:

(product + place)/2

Can someone suggest how can I do this? I'm not familiar with JS.

Thanks

Answer 1

where you want to display that value?? you can simply make a div named product_place and input field named product_place1 and use this code:

function show(){      
    document.getElementById('product_place').innerHTML = (product + place)/2;
    document.getElementById('product_place1').value = (product + place)/2;
}

The HTML part would be like this:

<button type="button" onClick="show()">show</button>

<div id="product_place">
  <script type="text/javascript">
      document.write((product + place)/2);
</script>
</div>
<input type="hidden" id="product_place1" name="product_place1">