JS caret to selection by pressing button in IE

I have a caret in the textarea (no selection). I need to make selection out of it by pressing a button.

For example: "This is a te|xt"

var range = document.selection.createRange ();
range.moveEnd('character');
range.select();
alert (range.htmlTe开发者_如何转开发xt);

But when I press button, the text on the button is being selected, not in the text field.

Is there a workaround for this?

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FOCUS to textfield is answer