get all mondays in calendar+js
function sundaysInMonth( m, y ) {
var days = new Date( y,m,0 ).getDate();
var sundays = [ 8 - (new Date( m +'/01/'+ y ).getDay()) ];
for ( var i = sundays[0] + 7; i < days; i += 7 ) {
sundays.push( i );
}
return sundays;
}
alert( sundaysInMonth( 10,2012 ) ); //=> [ 7,14,21,28 ]
alert( sundaysInMonth( 10,2012 ).length ); //=> 4