What is the use of jquery .each() function? code example

Example 1: jquery foreach

$.each( obj, function( key, value ) {
  alert( key + ": " + value );
});

Example 2: jq each loop

$( "div" ).each(function( index ) {
		//console.log( index )
	    modal_desc = $(this).length;
	    if(modal_desc > 20){
	    	//code
	    }
	});