calculate

[Mydas]

here is my code..what i want to do is..depenting from what the user presses from the 3 choices in the form..i want to have a different variable to calculate..ih the user presses the first option then the variable would be -->1
else if presses second option variable --> 2 else variable-->3

<script>

function foros()
{
var one= document.getElementById ('smth').value;
  

     {
      missing code  help me ;)
     }


	var result=0.15*variable
        document.write('taxis is: ',result)
</script>


select id="smth" name="Smth"  >
    <option  value="0" selected="selected" > no </option> 
    <option  value="1" >yes</option>
    <option  value="2" >maybe</option>
</select>

[devnull69]

You are reading the string(!) value of the selected option into the variable "one" already. All you need to do is to convert it to an integer

var one = document.getElementById('smth').value;
var variable = Number(one);
var result = 0.15*variable;