For this challenge you will determine the Run Length Encoding of a string.

functions.js

<script>
/*
Have the function RunLength(str) take the str parameter being passed
and return a compressed version of the string using the Run-length 
encoding algorithm. This algorithm works by taking the occurrence of 
each repeating character and outputting that number along with a single 
character of the repeating sequence. For example: "wwwggopp" would return
3w2g1o2p. The string will not contain any numbers, punctuation, or symbols. 
*/

function RunLength(str) { 
	var ctr=0,
	    output='',
	    data = str[0];

	for(var i=0; i<str.length; i++)
	{
		if(str[i] == data)
		{
			ctr++;
		}
		else
		{
			output += ctr+data;
			data = str[i];
			ctr = 1;
		}
	}

	output += ctr+data;
	return output;
}
</script>

``

error in this code : empty character literal at line number 13