var sentence1 = "<IMG SRC='images/tip_1.gif' WIDTH='311' HEIGHT='90' BORDER='0'>";
var sentence2 = "<IMG SRC='images/tip_2.gif' WIDTH='311' HEIGHT='90' BORDER='0'>";
var sentence3 = "<IMG SRC='images/tip_3.gif' WIDTH='311' HEIGHT='90' BORDER='0'>";
var sentence4 = "<A HREF='http://www.cast.org/bobby'><IMG SRC='images/tip_4.gif' WIDTH='311' HEIGHT='90' BORDER='0'></A>";
var sentence5 = "<IMG SRC='images/tip_5.gif' WIDTH='311' HEIGHT='90' BORDER='0'>";

var NoSentences = 5;
day = new Date();
seed = day.getTime();
RandNumber = parseInt(((seed - (parseInt(seed/1000,10) * 1000))/10)/100*NoSentences + 1,10);

if (RandNumber == (1)){
document.write(sentence1);  
}

if (RandNumber == (2)){
document.write(sentence2);  
}

if (RandNumber == (3)){
document.write(sentence3);  
}

if (RandNumber == (4)){
document.write(sentence4);  
}

if (RandNumber == (5)){
document.write(sentence5);  
}