function swapon1()  { document.img1.src="img/navigr1.gif"; }
function swapoff1() { document.img1.src="img/navig1.gif";  }
function swapon2()  { document.img2.src="img/navigr2.gif"; }
function swapoff2() { document.img2.src="img/navig2.gif";  }
function swapon3()  { document.img3.src="img/navigr3.gif"; }
function swapoff3() { document.img3.src="img/navig3.gif";  }
function swapon4()  { document.img4.src="img/navigr4.gif"; }
function swapoff4() { document.img4.src="img/navig4.gif";  }
function swapon5()  { document.img5.src="img/navigr5.gif"; }
function swapoff5() { document.img5.src="img/navig5.gif";  }
function swapon6()  { document.img6.src="img/navigr6.gif"; }
function swapoff6() { document.img6.src="img/navig6.gif";  }