Inserting some text to TextArea in Internet Explorer...

// input is the TextArea object
input.focus();
var oSel=document.selection;
if (oSel && oSel.createRange){
oSel.createRange().duplicate().text = insText;
}


for Gecko base:
var len = input.selectionEnd;
input.value = input.value.substr( 0, len ) + insText + input.value.substr(len);
input.setSelectionRange(len+insText.length,len+insText.length);