Google maps api use loop to set infowindow

everyone,I would like to use for-loop to set infowindows on my map. And I want the infowindow appear on the coordinates that I entered in the array,but it's doesn't work. Above are some parts of my codes,but I don't know what's wrong with my codes?

 var infoposition = [
	{lat:24.141328, lng:120.668040},
	{lat:24.145371, lng:120.671323},
	{lat:24.141720, lng:120.672332},
	{lat:24.142141, lng:120.671774}
];

    var contentspeed = [
    	'40km/h',
    	'42km/h',
    	'35km/h',
    	'40km/h'
    ];

    for (var i=0;i<(infoposition.length)-1;i++) {
      	var infowindow = new google.maps.InfoWindow({
        	content: contentspeed[i],
        	position: infoposition[i],
        	maxWidth:50,
        	pixelOffset: new google.maps.Size(-35, 100) 
      	});
    }

    infowindow.open(map,marker);