How to run a function after div has lost focus?

问题

I have several divs that each contain a form. Each of the forms has two input text fields. I am trying to trigger a function after div looses focus (meaning, not after one of the input text fields looses focus, but after totally new form in new div gains focus).

<div class='userInput' id='userInputID'>
   <div class='col1'>
    <form id='form1' method='post' action='BuyOrder.php'>
      <input type='text' name='r1' id='r1' value=''><br />
      <input type='text' name='b1' id='b1' value=''><br />
      <button id='button1' class='sendButton'>send</button>
    </form>
   </div>          
   <div class='colX'>
     <form id='formX' method='post' action='BuyOrder.php'>
      <input type='text' name='rX' id='rX' value=''><br />
      <input type='text' name='bX' id='bX' value=''><br />
      <button id='buttonX' class='sendButton'>send</button>
     </form>
   </div>    
   <div class='col2'>
     <form id='form2' method='post' action='BuyOrder.php'>
       <input type='text' name='r2' id='r2' value=''><br />
       <input type='text' name='b2' id='b2' value=''><br />
       <button id='button2' class='sendButton'>send</button>
     </form>
   </div>
</div>

And here is jquery code:

$('#userInputID').children().blur(function(){        
//some code   

})//end blur

Basically, I want the function to run when any of the divs with the class col1, colx or col2 looses focus. The jquery code above never even fires. Focusout doesn't work because that fires after each input text fields loose focus, even if the same div still has focus.

回答1:

The .blur() documentation would lead you to believe that you can use it this way; however, I believe you must explicitly trigger the blur on an element that is not a valid form element (e.g. input, select, etc.);

See this fiddle: http://jsfiddle.net/z7VYQ/

Based on your comment regarding validation, this fiddle shows you how to determine the currently focused form, and make adjustments to the other forms.

回答2:

How to fire a function after div has lost focus (blur)

Based on tests and on these pages 1, 2 it seems that blur does not bubble. But you can use a workaround. This updated fiddle shows that it works according to my understanding of your question:

for each div that is a child of the div id='userInputID'
create an event listener that fires after the div has lost focus (blur)

If you use the jQuery function on() you can capture focus and blur events.

$(document).ready(function() {
    $( "#userInputID" ).on( "blur", "div.onBlurTest", function() {        
        $( this ).toggleClass( "hasFocus" );
        $( this ).addClass( "hasLostFocus" );      
        $( this ).children("h2").text("Using on instead of blur");        
    }); 
});

And the html

<div class="userInput" id="userInputID">              
  <div class="col2 onBlurTest">
    <h2>Using on instead of blur</h2>
    <form id="form2" method="post" action="BuyOrder.php">
      <input type="text" name="r2" id="r2" value="" />
      <br />
      <input type="text" name="b2" id="b2" value="" />
      <br />
      <button id="button2" class="sendButton">send</button>
    </form>
  </div>
</div>

Fully working demo at fiddle with update dec 2013

As Chris Rockwell pointed out my former fiddle demo does not work if the tab key is used. I created a fork that works with the tab key as well

$(document).ready(function() {
  // Handler for .ready() called.

  $( "#userInputID" ).on( "focus", "div.onBlurTest", function() {
        $( this ).toggleClass( "hasFocus" );
        $( this ).removeClass( "hasLostFocus" );                 
  });

  $( "#userInputID" ).on( "blur", "div.onBlurTest", function() {
        $( this ).toggleClass( "hasFocus" );
        $( this ).removeClass( "hasLostFocus" );      
  });    
});

And simplified HTML

<div class="userInput" id="userInputID">              
      <div class="col2 onBlurTest">        
        <form id="form2" method="post" action="BuyOrder.php">
          <input type="text" name="r2" id="r2" value="" />
        </form>
      </div>
      <div class="col2 onBlurTest">     
        <form id="form2" method="post" action="BuyOrder.php">
            <input type="text" name="b2" id="b2" value="" />
        </form>
      </div>        
    </div>

Please let me know if you have further questions.

Some quotes

From the jQuery Api on blur

The blur event does not bubble in Internet Explorer. Therefore, scripts that rely on event delegation with the blur event will not work consistently across browsers. As of version 1.4.2, however, jQuery works around this limitation by mapping blur to the focusout event in its event delegation methods, .live() and .delegate().

来源：https://stackoverflow.com/questions/18029132/how-to-run-a-function-after-div-has-lost-focus

标签

jquery

events

blur

focusout