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Putting focus on a textbox in onchange event
原标题:

I am trying to get it so that when a certain value is put into a textbox, the focus will stay on the textbox(and an alert will be shown in production). I am trying to get this to work in Firefox 3.5.7 with no luck.

How can I make it so when a textbox is a certain value at onchange that it will stay focused/refocus on the textbox?

Live example is at http://jsbin.com/ipina

<body>
Enter your name: <input type="text" name="fname" id="fname" onchange="
  if(this.value== foo ){
    this.select();
    this.focus();
  }
  "  />
</body>

Also, I don t get any javascript errors or warnings in the Error Console on executing this code.

最佳回答

According to Javascript onchange different in IE and FireFox I needed to set the focus after the onchange event occurs, so I had to end up with something like this:

Enter your name: <input type="text" name="fname" id="fname" onblur="
  if(this.value== foo ){
    alert( bah );
    setTimeout( document.getElementById( fname ).focus();document.getElementById( fname ).select(); ,0);
  }
  "  />

And also I had to catch it when the focus was lost, not necessarily when the text was changed, so I had to use onblur instead of onchange.

Live: http://jsbin.com/ofeva

问题回答

When the onchange event is fired, the user is focused on the textbox.

Maybe you might want to use the blur event to re-focus on the textbox if the value is foo .

If you need instantaneous results, you should use onkeyup.

<body>
Enter your name: <input type="text" name="fname" id="fname" onkeyup="
  if(this.value== foo ){
    this.select();
    this.focus();
  }
  "  />
</body>




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