Некоторые эксперименты - неудачные
<input type="textarea" id="content1" name="content1" value="" readonly>
</br>quantity <input type = "textarea" id ="quantity" name = "quantity"/>
<iframe src="" id="items" name="items" style="width:100%;height:100%""></iframe>
<script>
var HTML = "<html><head></head><body><u>Document</u>"
+ "<b>HTML</b></body></html>";
items.document.open();
items.document.write(HTML);
items.document.close()
items.document.designMode = "on";
quantity.oninput = function() {
if(this.value )
content1.value = items.contentWindow.document.body.innerHTML;
}
</script>