Calculate expression in a single Jquery input field

I'm developing a calculator in HTML + JQuery where I have basic operations for it, however I need to implement the following:

When the user types in the input field an expression type: (5 * 5) +4 JQuery the operation and show the result. any idea how you could be doing this?

$("input[name=exp]").click(function(){
    valor = $("#result").val();
    $("#result").val(valor);
});

follows my JQuery code:

$( function(){

    var v1, v2, op;

    $("input[name=btn]").click(function(){
        $("#result").val($("#result").val() + $(this).val());
    });

    $("input[name=ce]").click(function(){
        $("#result").val('');
        $("#op").text('');
    });

    $("input[name=soma]").click(function(){
        if($("#result").val() != ''){
            v1 = parseFloat($("#result").val());
            $("#result").val('');
            op = "soma";
            $("#op").text($(this).val());
        }else{
            alert("Insira um valor para efetuar a operação");
        }
    });

    $("input[name=menos]").click(function(){
        if($("#result").val() != ''){
            v1 = parseFloat($("#result").val());
            $("#result").val('');
            op = "menos";
            $("#op").text($(this).val());
        }else{
            alert("Insira um valor para efetuar a operação");
        }
    });

    $("input[name=vezes]").click(function(){
        if($("#result").val() != ''){
            v1 = parseFloat($("#result").val());
            $("#result").val('');
            op = "vezes";
            $("#op").text($(this).val());
        }else{
            alert("Insira um valor para efetuar a operação");
        }
    });

    $("input[name=divisao]").click(function(){
        if($("#result").val() != ''){
            v1 = parseFloat($("#result").val());
            $("#result").val('');
            op = "divisao";
            $("#op").text($(this).val());
        }else{
            alert("Insira um valor para efetuar a operação");
        }
    });

    $("input[name=igual]").click(function(){
        if($("#result").val() != ''){
            v2 = parseFloat($("#result").val());

            if(op == "soma"){
                $("#result").val(v1 + v2);
            }else if(op == "menos"){
                $("#result").val(v1 - v2);
            }else if(op == "vezes"){
                $("#result").val(v1 * v2);
            }else{
                $("#result").val(v1 / v2);
            }
        }else{
            alert("Insira um valor para efetuar a operação");
        }
    });

    $("input[name=apagar").click(function(){
        var len = $("#result").val().length;

        var valor = $("#result").val();
        valor = valor.replace(valor.charAt(len - 1), "");
        $("#result").val(valor);
    });

});