HTML - Habilitar e inhabilitar Radio Button y formularios HTML y JS

<label><input type="radio" id="rdoFrm1" name="formSelect" value="1"/>Formulario 1</label>

<label><input type="radio" id="rdoFrm2" name="formSelect" value="2"/>Formulario 2</label>

<form id="frm1">

	<fieldset>

		<legend>Formulario 1:</legend>

		<input type="text" />

		<input type="text" />

		<input type="text" />

	</fieldset>

</form>

<form id="frm2">

	<fieldset>

		<legend>Formulario 2:</legend>

		<input type="text" />

		<input type="text" />

		<input type="text" />

	</fieldset>

</form>

<script>

document.getElementById('rdoFrm1').addEventListener('click',selectForm);

document.getElementById('rdoFrm2').addEventListener('click',selectForm);

document.getElementById('rdoFrm1').click();

function selectForm(){

	formularios = document.querySelectorAll('form');

	for(formulario of formularios){

		inputs = formulario.querySelectorAll('input');

		valorDisabled = ('frm'+this.value != formulario.attributes.id.value)?true:false;

		for(input of inputs){

			input.disabled=valorDisabled;

		}

	}

}

</script>