<input type="number" name="val1" id="val1" value="" width="20">
<input type="number" name="val2" id="val2" value="" width="20">
<input type="number" name="val3" id="val3" value="" width="20">
<input type="button" name="btnCalcular" onclick = "tipoTriangulo(val1,val2,val3)" value="calcular">
<script type="text/javascript">
function tipoTriangulo(val1,val2,val3){
var val1 = document.getElementById("val1").value;
var val2 = document.getElementById("val2").value;
var val3 = document.getElementById("val3").value;
if (val1 + val2 > val3){
if (val1 == val2 && val1 == val3);
alert('Triângulo Equilátero');
else if((val1 == val2 || val2 == val3 || val1 == val3));
alert('Triângulo Isósceles');
else if((val1 != val2) && (val2 != val3) && (val1 != val3));
alert('Triângulo Escaleno');
else
}
alert(‘Nao forma um triangulo’);
}
</body>