Javascript中自动切换焦点实现代码

  

复制代码 代码如下:

  <!DOCTYPE html>

  <html>

  <head>

  <meta charset="UTF-8">

  <title>test javascript</title>

  <script type="text/javascript">

  window.onload = function() {

  var EventUtil = {

  addhandler:function(element,type,handler) {

  if(element.addEventListenter) {

  element.addEventListenter(type,handler,false);

  } else if (element.attachEvent) {

  element.attachEvent("on"+type,handler);

  } else {

  element["on"+type] = handler;

  }

  },

  getEvent:function(event) {

  return event?event:window.event;

  },

  getTarget:function() {

  return event.target || event.srcElement;

  },

  preventDefault:function() {

  if(event.preventDefault) {

  event.preventDefault();

  } else {

  event.returnValue = false;

  }

  },

  stopPropagation:function() {

  if(event.stopPropagation) {

  event.stopPropagation();

  } else {

  event.cancelBuddle = true;

  }

  },

  removehandler:function(element,type,handler) {

  if(element.removeEventListenter) {

  element.addEventListenter(type,handler,false);

  } else if (element.detachEvent) {

  element.detachEvent("on"+type,handler);

  } else {

  element["on"+type] = null;

  }

  },

  getCharCode: function(event) {

  if(typeof event.charCode == "number") {

  return event.charCode;

  } else {

  return event.keyCode;

  }

  },

  getClipboardText: function(event) {

  var clipboardData = event.clipboardData || window.clipboardData;

  return clipboardData.getData("text");

  },

  setClipboardText: function(event,value) {

  if(event.clipboardData) {

  return event.clipboardData.setData("text/plain",value);

  } else if(window.clipboardData){

  return window.clipboardData.setData("text",value);

  }

  }

  }

  var textarea = document.forms[0].elements["text"];

  var button = document.getElementById("button");

  (function() {

  function tabForward(event) {

  event = EventUtil.getEvent(event);

  var target = EventUtil.getTarget(event);

  if(target.value.length == target.maxLength) {

  var form = target.parentElement;

  for(var i=0,len = form.elements.length;i<len-1;i++) {

  if(form.elements[i] == target) {

  form.elements[i+1].focus();

  return ;

  }

  }

  }

  }

  var textTel1 = document.getElementById("txtTel1");

  var textTel2 = document.getElementById("txtTel2");

  var textTel3 = document.getElementById("txtTel3");

  EventUtil.addhandler(textTel1,"keyup",tabForward);

  EventUtil.addhandler(textTel2,"keyup",tabForward);

  EventUtil.addhandler(textTel3,"keyup",tabForward);

  })();

  }

  </script>

  </head>

  <body>

  <form>

  <input type="text" name="tel1" id="txtTel1" maxlength="3" />

  <input type="text" name="tel2" id="txtTel2" maxlength="3" />

  <input type="text" name="tel3" id="txtTel3" maxlength="3" />

  </form>

  </body>

  </html>