function getHeaderParameterValue(sHeaderValue, sParameterName) {
		var iParamIndex,
			aHeaderParts = sHeaderValue.split(";"),
			aMatches;

		sParameterName = sParameterName.toLowerCase();
		for (iParamIndex = 1; iParamIndex < aHeaderParts.length; iParamIndex += 1) {
			// remove possible quotes via reg exp
			// RFC7231: parameter = token "=" ( token / quoted-string )
			aMatches = rHeaderParameter.exec(aHeaderParts[iParamIndex]);
			if (aMatches[1].toLowerCase() === sParameterName) {
				return aMatches[2] || aMatches[3];
			}
		}
	}
Extracts value of the parameter with the specified <code>sParameterName</code>
from the specified <code>sHeaderValue</code>.

@param {string} sHeaderValue
  HTTP header value e.g. "application/json;charset=utf-8"
@param {string} sParameterName
  Name of HTTP header parameter e.g. "charset"
@returns {string|undefined} The HTTP header parameter value or <code>undefined</code> if the
  parameter is not found