richtexttransformer.js

var lines = document.getElementById('textArea').value.split("\n");
var prev = 0, str = "", blankLines = 0, total = "";

for(var n in lines) {
	str = b[n];
	
	if(str === "") {
		blankLines++;
		
		if(n == (lines.length-1) && blankLines !== 0) {
			total += "rtItem.addNewLine("+ blankLines +");\n";
		}
		    
	} else {
		if(prev === "") {
			total += "rtItem.addNewLine("+ blankLines +");\n";
			blankLines = 0;

		} else {
			total += "rtItem.appendText(\""+ str +"\");\n";
		}
	}
		
	prev = str;
}

alert(total);