code: function trimUrlValue(value) {
      var beginSlice, endSlice;
      value = value.trim();
      beginSlice = value.charAt(0) === '\'' || value.charAt(0) === '"' ? 1 : 0;
      endSlice = value.charAt(value.length - 1) === '\'' ||
          value.charAt(value.length - 1) === '"' ?
          -1 : undefined;
      return value.slice(beginSlice, endSlice).trim();
  }
docs: Trims whitespace and quotes from css 'url()' values
  
  @param {string} value - string to trim
  @returns {string} - the trimmed string