Uncaught Error SyntaxError: Unexpected token = [closed]

I'm working on a payroll and the function that calculates the IR (income tax) is with some mistake that I honestly can not find at all. If anyone can help me.

function desconto_ir()
    {var salario = document.getElementById("salario_bruto").value;
    var inss = document.getElementById("valor_calculado_11").value;
    var esposa = document.getElementById("casado").value;
    var dp1 = document.getElementById("filhos").value;
    var dp2 = document.getElementById("dp_22_24").value;
    var dependentes = eval(esposa + dp1 + dp2);
    var base_de_calculo = (parseFloat(salario - inss - (179.71 * dependentes))).toFixed(2);
    if (base_de_calculo <= 1787.77)
        {document.getElementById("valor_ir").innerHTML = base_de_calculo;}
    else if (base_de_calculo >= 1787.78 && <= 2679.29)
        {document.getElementById("valor_ir").innerHTML = (parseFloat((base_de_calculo * 0.075) - 134.08)).toFixed(2);}
    else if (base_de_calculo >= 2679.30 && <= 3572.43)
        {document.getElementById("valor_ir").innerHTML = (parseFloat((base_de_calculo * 0.15) - 335.03)).toFixed(2);}
    else if (base_de_calculo >= 3572.44 && <= 4463.81)
        {document.getElementById("valor_ir").innerHTML = (parseFloat((base_de_calculo * 0.225) - 602.96)).toFixed(2);}
    else
        {document.getElementById("valor_ir").innerHTML = (parseFloat((base_de_calculo * 0.275) - 826.15)).toFixed(2);}}