<script>
function verifica(){
senha = document.getElementById("senha").value;
forca = 0;
mostra = document.getElementById("mostra");
if((senha.length >= 4) && (senha.length <= 7)){
forca += 10;
}else if(senha.length>7){
forca += 25;
}
if(senha.match(/[a-z]+/)){
forca += 10;
}
if(senha.match(/[A-Z]+/)){
forca += 20;
}
if(senha.match(/\d+/)){
forca += 20;
}
if(senha.match(/\W+/)){
forca += 25;
}
return mostra_res();
}
function mostra_res(){
if(forca < 30){
mostra.innerHTML = '<tr><td bgcolor="red" width="'+forca+'"></td><td>Fraca </td></tr>';
}else if((forca >= 30) && (forca < 60)){
mostra.innerHTML = '<tr><td bgcolor="yellow" width="'+forca+'"></td><td>Justa </td></tr>';;
}else if((forca >= 60) && (forca < 85)){
mostra.innerHTML = '<tr><td bgcolor="blue" width="'+forca+'"></td><td>Forte </td></tr>';
}else{
mostra.innerHTML = '<tr><td bgcolor="green" width="'+forca+'"></td><td>Excelente </td></tr>';
}
}
</script>
</head>
<body>
<center><h1><font color="red">Veja o nível da senha digitada</font></h1></center>
<form name="teste" id="teste" onsubmit="return false">
Senha: <input type="password" name="senha" id="senha" onkeyup="javascript:verifica()" />
<table id="mostra"></table>