get.js

/**
 * @module  caret-position/get
 *
 * Adoption from code at
 * http://blogs.nitobi.com/alexei/wp-content/uploads/2008/01/getcaretselection3.js
 *
 * @return the caret position in a text field
 */
module.exports = function (input) {
	var docObj = input.ownerDocument,
		result = { start:0, end:0, caret:0 };

	if (navigator.appVersion.indexOf("MSIE")!=-1) {
		if (input.tagName == "TEXTAREA") {
			if (input.value.charCodeAt(input.value.length-1) < 14) {
				input.value = input.value.replace(/34/g,'') + String.fromCharCode(28);
			}
			var range = docObj.selection.createRange(),
				rangeCopy = range.duplicate();

			rangeCopy.moveToElementText(input);
			rangeCopy.setEndPoint('StartToEnd', range);
			result.end = input.value.length - rangeCopy.text.length;

			rangeCopy.setEndPoint('StartToStart', range);
			result.start = input.value.length-rangeCopy.text.length;
			result.caret = result.end;

			if (input.value.substr(input.value.length-1) == String.fromCharCode(28)) {
				input.value = input.value.substr(0, input.value.length-1);
			}
		} else {
			var range = docObj.selection.createRange(),
				rangeCopy = range.duplicate();

			result.start = 0 - rangeCopy.moveStart('character', -100000);
			result.end = result.start + range.text.length;
			result.caret = result.end;
		}
	} else {
		var isNumber = input.type === 'number'
		if (isNumber) input.type = 'text'
		result.start = input.selectionStart;
		result.end = input.selectionEnd;
		result.caret = result.end;
		if (isNumber) input.type = 'number'
	}
	if (result.start < 0) {
		 result = { start:0, end:0, caret:0 };
	}
	return result;
};