SOURCE

console 命令行工具 X clear

                    
>
console
var inputBox = document.querySelector('#inputbox'),
    check = document.querySelector('#check');
  inputBox.addEventListener('keyup',function(){
    if (inputBox.value.length <=6) {
      check.innerText = '密码长度要大于6'
    } else{
      var rank = fnCheck(inputBox.value);
      if (rank >= 4) {
        check.innerText = '强';
      }else if(rank >1){
        check.innerText = '中';
      }else{
        check.innerText = '弱';
      }
    }
  })
  function fnCheck(val){
    var num = 0,
      hasLowerCase = val.search(/[a-z]/),
      hasUperCase = val.search(/[A-Z]/),
      hasNum = val.search(/[0-9]/);
    var others = val.split('').some(function(v){
      var asc = v.charCodeAt();
      return ((asc>32 && asc<48) || (asc>57 && asc<65) || (asc>90 && asc<97) || (asc>122 && asc<127));
    });
    if (hasLowerCase>-1) {
      num++;
    }
    if(hasUperCase>-1){
      num++;
    }
    if(hasNum>-1){
      num++;
    }
    if (others) {
      num = num+2;
    }
    return num;
  }
<input type="password" placeholder='请输入密码' id='inputbox'/><br />
密码强度:<span id="check"></span>