Question

This is a simple dropdown with values. I’m trying to pull the values as currency then add.

The values aren’t being added (1+1=2 or 1+2=3) but instead are concatenating (1+1=11 or 1+2=12). Where am I going wrong here?:

<script>
    function displayResult()
    {
        var strm=document.getElementById("matt").options[document.getElementById("matt").selectedIndex];
        var t=strm.text.search("\\\$");
        var strb=document.getElementById("box").options[document.getElementById("box").selectedIndex];
        var b=strb.text.search("\\\$");
        var x=strm.text.substr(t+1);
        var y=strb.text.substr(b+1);
        var math= x + y;

        alert(strm.text.substr(t+1));
        alert(strb.text.substr(b+1));
        alert(math);
    }
</script>

<form>
    Select #1:
    <select id="matt">
        <option>$1.00</option>
        <option>$2.00</option>
    </select>

    <br />
    Select #2:
    <select id="box">
        <option>$3.00</option>
        <option>$4.00</option>
    </select>

</form>

<button type="button" onclick="displayResult()">Display index</button>

Answer 1

Use parseInt() to cast your strings as integers.

var math= parseInt(x,10) + parseInt(y,10);

See https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/parseInt