User:Gerbrant/edit/selection.js

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module("Gerbrant.edit.selection", new function()
{
	if(document.selection && !is_gecko) // IE
		this.replaceTextareaSelection = function(t, f)
		{
			t.focus();
			var r = document.selection.createRange()
			var selText = r.text;
			if(f) r.text = f(selText);
			return selText;
		}
	else // Others
		this.replaceTextareaSelection = function(t, f)
		{
			var start = t.selectionStart;
			if(start == undefined) (function(m)
			{
				alert(m);
				throw new Error(m);
			})("Can't access the selection in textareas because your browser neither supports document.selection for this, nor does it support selectionStart and selectionEnd.");
			var end = t.selectionEnd;
			var text = t.value;
			var selText = text.substring(start, end);
			if(f)
			{
				var scrollTop = t.scrollTop;
				var newText = f(selText);
				t.value = text.substring(0, start) + newText + text.substring(end);
				t.scrollTop = scrollTop;
				t.selectionEnd = (t.selectionStart = start) + newText.length;
				setTimeout(function()
				{
					t.selectionEnd = (t.selectionStart = start) + newText.length;
				}, 0);
			}
			return selText;
		}
	this.replaceSelection = function(f)
	{
		return this.replaceTextareaSelection(document.getElementById("wpTextbox1"), f);
	}
});