How to get the user input from buttons to display in the text box using function (for-loop)?

Question

How to get the numbers displayed in the display textbox when the user clicks the number buttons? I do not know what to put in my numInputF() function, I want to use a for-loop function, but I do not know how.

    <script>

        var initialMoney = 1000; //Customer's initial money is $1000
        var display;

        /* Set the "Type amount and select operation to blank." */
        function setBlankF(){
            document.getElementById("display").value = "";
        }

        /* Gets the user input when buttons are clicked. */
        function numInputF(){

        }

This is my body part. I know that I should put something on the onclick button, but I have not figured out how to make my function, which is why it is blank.

        <table border="1">

            <caption>ATM 360</caption>

                <tr>
                    <td colspan="4">
                        <input type="text" id="display" value="Type amount and select operation" size="30" onclick="setBlankF()">
                    </td>
                </tr>

                <tr>
                    <td>
                        <input type="button" value="1" onclick="">
                    </td>
                    <td>
                        <input type="button" value="2" onclick="">
                    </td>
                    <td>
                        <input type="button" value="3" onclick="">
                    </td>
                    <td>
                        <input type="button" value="Withdrawal" id="withdraw" onclick="">
                    </td>
                </tr>

                <tr>
                    <td>
                        <input type="button" value="4" onclick="">
                    </td>
                    <td>
                        <input type="button" value="5" onclick="">
                    </td>
                    <td>
                        <input type="button" value="6" onclick="">
                    </td>
                    <td>
                        <input type="button" value="Deposit" id="deposit" onclick="">
                    </td>
                </tr>

                <tr>
                    <td>
                        <input type="button" value="7" onclick="">
                    </td>
                    <td>
                        <input type="button" value="8" onclick="">
                    </td>

                    <td>
                        <input type="button" value="9" onclick="">
                    </td>

                    <td>
                        <input type="button" value="Retype" id="retype" onclick="">
                    </td>
                </tr>

                <tr>
                    <td>
                    </td>
                    <td>
                        <input type="button" value="0" onclick="">
                    </td>
                    <td>
                    </td>
                    <td>
                        <input type="button" value="End" id="end" onclick="">
                    </td>
                </tr>
        </table>

Thank you in advance.

Answer 1

First attach the click event to all the buttons, so get all buttons elements with type=button using .querySelectorAll() then loop through them and pick one by one buttons[i] and attach the click event using .addEventListener this click will lead us to the function numInputF as defined in the passed arguments :

var buttons = document.querySelectorAll('[type="button"]');

for(var i=0;i<buttons.length;i++){
     buttons[i].addEventListener("click", numInputF, false);
}

Then in your function you could get the value like :

function numInputF(){
    alert(this.value);
}

Hope this helps.

 var buttons = document.querySelectorAll('[type="button"]'); for(var i=0;i<buttons.length;i++){ buttons[i].addEventListener("click", numInputF, false); } function numInputF(){ alert(this.value); } 

 <table border="1"> <caption>ATM 360</caption> <tr> <td colspan="4"> <input type="text" id="display" value="Type amount and select operation" size="30" onclick="setBlankF()"> </td> </tr> <tr> <td> <input type="button" value="1" onclick=""> </td> <td> <input type="button" value="2" onclick=""> </td> <td> <input type="button" value="3" onclick=""> </td> <td> <input type="button" value="Withdrawal" id="withdraw" onclick=""> </td> </tr> <tr> <td> <input type="button" value="4" onclick=""> </td> <td> <input type="button" value="5" onclick=""> </td> <td> <input type="button" value="6" onclick=""> </td> <td> <input type="button" value="Deposit" id="deposit" onclick=""> </td> </tr> <tr> <td> <input type="button" value="7" onclick=""> </td> <td> <input type="button" value="8" onclick=""> </td> <td> <input type="button" value="9" onclick=""> </td> <td> <input type="button" value="Retype" id="retype" onclick=""> </td> </tr> <tr> <td> </td> <td> <input type="button" value="0" onclick=""> </td> <td> </td> <td> <input type="button" value="End" id="end" onclick=""> </td> </tr> </table>