js 字符串：敏感词过滤、文本框监测、验证码

//文本框监测   <input type="text" id="txt"> <span id="tip"></span> <script> /* 长度为6-16 全是数字为弱 有特殊字符为强 其他为中 */ //给txt绑定事件 var str = "@#$%^&*"; txt.oninput = function () { //判断长度 if(txt.value.length < 6 || txt.value.length > 16){ return tip.innerHTML = "长度不合法"; } //判断数字 if(Number(txt.value) == txt.value){ return tip.innerHTML = "密码强度弱"; } //判断是否含有特殊字符 for(var i = 0; i < str.length; i++){ if(txt.value.indexOf(str[i]) != -1){ return tip.innerHTML = "密码强度强"; } }   }   </script>     //敏感词过滤   <input type="text" id="txt"> <button id="btn">提交</button> <span id="tip"></span> <script> var arr = ["sb", "fuck", "md", "laji"]; //给btn绑定事件 btn.onclick = function(){ var txtvalue = txt.value; for(var i = 0; i < arr.length; i++){ txtvalue = txtvalue.replace(arr[i], "*"); } tip.innerHTML = txtvalue; }
  </script>   //验证码
    <span id="code"></span> <button id="btn">获取验证码</button> <script> //给btn绑定事件 btn.onclick = function () { var str = ""; var num = null; //获取4个随机数 for(var i = 0; i < 4; i++){ num = parseInt(Math.random() * 74 + 48); //判断num是否合格 if(num >= 48 && num <= 57 || num >= 65 && num <= 90 || num >= 97 && num <= 122){ str += String.fromCharCode(num); }else{ i--; } }   code.innerHTML = str; code.style.color = randomColor(); } //随机颜色 function randomColor(){ var str = "0123456789abcdf"; var color ="#"; for(var i = 0; i < 6; i++){ color += str[parseInt(Math.random() * 16)]; } return color; }