Prompt command in Functions

Question

Can I use a Prompt command to define the argument of a function?
For example is there anything wrong in a part of code like this one?

<button onclick="toCelsius()">From Fahrenheit To Celsius</button>
<script>
function toCelsius(Fahreneit){
return (5/9)*(Fahreneit-32);
document.write("The temperature is " + toCelsius(prompt("Enter Fahrenheit value")) + "° Celsius");
}
</script>

Answer 1

That won't work as you can't get past the return. This will:
<button onclick="toCelsius()">From Fahrenheit To Celsius</button>
<script>
function toCelsius() {
function convert(Fahreneit){
return (5/9)*(Fahreneit-32);
}
document.write("The temperature is " + convert(prompt("Enter Fahrenheit value")) + "° Celsius");
}

Answer 2

Thanks!!