Multiplying an input with a select option value : there everyone I am really new in this field and have a lot to learn yet. My question is that I am building an order for my own website and in this form I want users to select an option from a drop-down menu. Now I want each of those values to have a specific price and then when they move down to the quantity section they would be able to select the quantity of the product.
Now I want to print the value of (any selected product i.e. its price) * (the quantity or no. of products). I know that it requires a script but I can't figure out the script. Any help in this regard would be highly appreciated. I'm not sure but I want it to be something like if product 1 is selected then multiply the price of product 1 with its quantity and display results. 
this is the code.

Please Select Your Academic Level

    <select name="ac_level" required="">
    <option id="1" value="highschool">Highschool</option>
    <option id="2"value="college">College</option>
    <option id="3" value="university">University</option>
    <option id="4" value="masters">Masters</option>
    <option id="5" value="phd">PhD</option>
    </select>

Number of Pages 

    <input name="pages" required="" type="number" min=1 />

