var randHdr = randRange(1,16);

if (randHdr == 1) {
document.write('<img src="img/imagenes_aleatorias/eva.jpg">')
} else if (randHdr == 2) {
document.write('<img src="img/imagenes_aleatorias/gianna.jpg">')
} else if (randHdr == 3) {
document.write('<img src="img/imagenes_aleatorias/maria.jpg">')
} else if (randHdr == 4) {
document.write('<img src="img/imagenes_aleatorias/lisbeth.jpg">')
} else if (randHdr == 5) {
document.write('<img src="img/imagenes_aleatorias/lisbet.jpg">')
} else if (randHdr == 6) {
document.write('<img src="img/imagenes_aleatorias/goniometro.jpg">')
} else if (randHdr == 7) {
document.write('<img src="img/imagenes_aleatorias/coulter.jpg">')
} else if (randHdr == 8) {
document.write('<img src="img/imagenes_aleatorias/francys.jpg">')
} else if (randHdr == 9) {
document.write('<img src="img/imagenes_aleatorias/juancarlos.jpg">')
} else if (randHdr == 10) {
document.write('<img src="img/imagenes_aleatorias/lab_1.jpg">')
} else if (randHdr == 11) {
document.write('<img src="img/imagenes_aleatorias/torbellino.jpg">')
} else if (randHdr == 12) {
document.write('<img src="img/imagenes_aleatorias/microscopio.jpg">')
} else if (randHdr == 13) {
document.write('<img src="img/imagenes_aleatorias/tensiometro_gota.jpg">')
} else if (randHdr == 14) {
document.write('<img src="img/imagenes_aleatorias/manometro.jpg">')
} else if (randHdr == 15) {
document.write('<img src="img/imagenes_aleatorias/cetametro.jpg">')
} else if (randHdr == 16) {
document.write('<img src="img/imagenes_aleatorias/mairis.jpg">')
}