CSS Change Jquery : i am javascript

• .css() – jQuery API
  "Description: Set one or more CSS properties for the set of matched elements.
  
  version added: 1.0.css( propertyName, value )
  
  propertyNameA CSS property name.
  
  valueA value to set for the property.
  version added: 1.4.css( propertyName, function(index, value) )
  
  propertyNameA CSS property name.
  
  function(index, value)A function returning the value to set. this is the current element. Receives the index position of the element in the set and the old value as arguments.
  version added: 1.0.css( map )
  
  mapA map of property-value pairs to set.
  
  As with the .prop() method, the .css() method makes setting properties of elements quick and easy. This method can take either a property name and value as separate parameters, or a single map of key-value pairs (JavaScript object notation).
  
  Also, jQuery can equally interpret the CSS and DOM formatting of multiple-word properties. For example, jQuery understands and returns the correct value for both .css({'background-color': '#ffe', 'border-left': '5px solid #ccc'}) and .css({backgroundColor: '#ffe', borderLeft: '5px solid #ccc'}). Notice that with the DOM notation, quotation marks around the property names are optional, but with CSS notation they're required due to the hyphen in the name.
  
  When using .css() as a setter, jQuery modifies the element's style property. For example, $('#mydiv').css('color', 'green') is equivalent to document.getElementById('mydiv').style.color = 'green'. Setting the value of a style property to an empty string — e.g. $('#mydiv').css('color', '') — removes that property from an element if it has already been directly applied, whether in the HTML style attribute, through jQuery's .css() method, or through direct DOM manipulation of the style property. It does not, however, remove a style that has been applied with a CSS rule in a stylesheet or