app.js

function solveEqn(clicked_id){
    let eqn = clicked_id;
    let input = document.getElementById("eqn");

    if(eqn == "point"){
        input.value += "."
    }
    else if(eqn == "plus"){
        input.value += "+"
    }
    else if(eqn == "sub"){
        input.value += "-"
    }
    else if(eqn == "multiply"){
        input.value += "*"
    }
    else if(eqn == "div"){
        input.value += "/"
    }
    else if(eqn == "modulus"){
        input.value += "%"
    }
    else if(eqn == "equal"){
        input.value = eval(input.value)
    }
    else if(eqn == "reset"){
        input.value = null
    }
    else {
        input.value += eqn;
    }

}

document.onkeypress = function(e) {
    let input = document.getElementById("eqn");
    e = e || window.event;
    let key = e.keyCode;
    let keyName = e.key;
    let keyPressed = String.fromCharCode(key);


        if(keyName == "Enter" || keyName == "Equal"){
            input.value = eval(input.value)
        }
}