In jQuery, there are two way to change the width of an element.

One way is using .css('width') and other way is using .width().

For example:

$('#mydiv').css('width','300px');

$('#mydiv').width(100);

★ The difference in .css('width') and .width() is the data type of value we specify or return from the both functions.

★ In .css('width') we have to add "px" in the width value while in .width() we don't have to add.

★ When you want to get the width of "mydiv" element then .css('width') will return '300px' while .width() will return only integer value 300.