src/lay/modules/layedit.js
function(iframeWin, iframe, textArea, set){
    var iframeDOM = iframeWin.document, body = $(iframeDOM.body);
    body.on('keydown', function(e){
      var keycode = e.keyCode;
      //处理回车
      if(keycode === 13){
        var range = Range(iframeDOM);
        var container = getContainer(range)
        ,parentNode = container.parentNode;
        
        if(parentNode.tagName.toLowerCase() === 'pre'){
          if(e.shiftKey) return
          layer.msg('请暂时用shift+enter');
          return false;
        }
        iframeDOM.execCommand('formatBlock', false, '<p>');
      }
    });
    
    //给textarea同步内容
    $(textArea).parents('form').on('submit', function(){
      var html = body.html();
      //IE8下将标签处理成小写
      if(device.ie == 8){
        html = html.replace(/<.+>/g, function(str){
          return str.toLowerCase();
        });
      }
      textArea.value = html;
    });
    
    //处理粘贴
    body.on('paste', function(e){
      iframeDOM.execCommand('formatBlock', false, '<p>');
      setTimeout(function(){
        filter.call(iframeWin, body);
        textArea.value = body.html();
      }, 100); 
    });
  }
function(iframeWin, iframe, textArea, set){
    var iframeDOM = iframeWin.document, body = $(iframeDOM.body);
    body.on('keydown', function(e){
      var keycode = e.keyCode;
      //处理回车
      if(keycode === 13){
        var range = Range(iframeDOM);
        var container = getContainer(range)
        ,parentNode = container.parentNode;
        
        if(parentNode.tagName.toLowerCase() === 'pre'){
          if(e.shiftKey) return
          layer.msg('请暂时用shift+enter');
          return false;
        }
        iframeDOM.execCommand('formatBlock', false, '<p>');
      }
    });
    
    //给textarea同步内容
    $(textArea).parents('form').on('submit', function(){
      var html = body.html();
      //IE8下将标签处理成小写
      if(device.ie == 8){
        html = html.replace(/<.+>/g, function(str){
          return str.toLowerCase();
        });
      }
      textArea.value = html;
    });
    
    //处理粘贴
    body.on('paste', function(e){
      iframeDOM.execCommand('formatBlock', false, '<p>');
      setTimeout(function(){
        filter.call(iframeWin, body);
        textArea.value = body.html();
      }, 100); 
    });
  }
iframe初始化