src/util/WWUtil.js
function(subjectString, searchString, position) {
                position = position || 0;
                return subjectString.substr(position, searchString.length) === searchString;
            }
function(subjectString, searchString, position) {
                position = position || 0;
                return subjectString.substr(position, searchString.length) === searchString;
            }
function ( subjectString , searchString , position ) { position = position || 0 ; return subjectString . substr ( position , searchString . length ) === searchString ; }
Determines whether subjectString begins with the characters of searchString.
@param {String} subjectString The string to analyse.
@param {String} searchString The characters to be searched for at the start of subjectString.
@param {Number} position The position in subjectString at which to begin searching for searchString; defaults to 0.
@return {Boolean} true if the given characters are found at the beginning of the string; otherwise, false.
Determines whether subjectString begins with the characters of searchString .