可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试):

问题:

<html>
 <body>
  <script type="text/javascript">

   function smth() {

    if (document.getSelection) {
    var str = document.getSelection();
    if (window.RegExp) {
      var regstr = unescape("%20%20%20%20%20");
      var regexp = new RegExp(regstr, "g");
      str = str.replace(regexp, "");
    }
    } else if (document.selection && document.selection.createRange) {
     var range = document.selection.createRange();
     var str = range.text;
    }   

    alert(str);
   }
  </script>   

    <iframe id="my"  width="300" height="225">
   .....some html ....
    </iframe>      

    <a href="#" onclick="smth();">AA</a>
 </body>    
</html>

with smth function i can get selected text from some div, but it doesnt work with iframe. any ideas how to get selected text from iframe ?

回答1:

document.getSelection

Is on the outer document. To get the selection of the document in the iframe you need to grab the inner document:

var iframe= document.getElementById('my');
var idoc= iframe.contentDocument || iframe.contentWindow.document; // ie compatibility

idoc.getSelection()

Note however that WebKit does not support document.getSelection() or document.selection. Try replacing it with window.getSelection() which works in both Firefox and WebKit, but returns a selection object (a collection/wrapper around Ranges), which needs stringing:

var idoc= iframe.contentDocument || iframe.contentWindow.document;
var iwin= iframe.contentWindow || iframe.contentDocument.defaultView;

''+iwin.getSelection()

I'm not sure what the point of this is:

if (window.RegExp) {
  var regstr = unescape("%20%20%20%20%20");
  var regexp = new RegExp(regstr, "g");
  str = str.replace(regexp, "");
}

RegExp is basic JavaScript dating back to the very earliest version; it will always be there, you don't have to sniff for it. The URL-encoding of multiple spaces is quite unnecessary. You don't even need RegExp as such, a string replace could be written as:

str= str.split('     ').join('');

回答2:

You can't access data inside an iframe that is from a domain different than yours. This is due to the Same origin policy.

回答3:

You need to get the selection from the document/window in the iframe.

function getIframeSelectionText(iframe) {
  var win = iframe.contentWindow;
  var doc = win.document;

  if (win.getSelection) {
    return win.getSelection().toString();
  } else if (doc.selection && doc.selection.createRange) {
    return doc.selection.createRange().text;
  }
}

var iframe = document.getElementById("my");
alert(getIframeSelectionText(iframe));

回答4:

Following code will return the selected text.

function getSelectedText(frameId) { 
    // In ExtJS use: 
    // var frame = Ext.getDom(frameId); 
    var frame = document.getElementById(frameId); 

    var frameWindow = frame && frame.contentWindow; 
    var frameDocument = frameWindow && frameWindow.document; 

    if (frameDocument) { 
        if (frameDocument.getSelection) { 
            // Most browsers 
            return String(frameDocument.getSelection()); 
        } 
        else if (frameDocument.selection) { 
            // Internet Explorer 8 and below 
            return frameDocument.selection.createRange().text; 
        } 
        else if (frameWindow.getSelection) { 
            // Safari 3 
            return String(frameWindow.getSelection()); 
        } 
    } 

    /* Fall-through. This could happen if this function is called 
       on a frame that doesn't exist or that isn't ready yet. */ 
    return ''; 
}

Hope this will help to someone.

回答5:

This code works in all modern browsers:

var iframe = document.getElementById('my');
var idoc = iframe.contentDocument || iframe.contentWindow.document; // ie compatibility
var text = idoc.getSelection().toString();