function coloriseTheTable(){
	var allTables=document.getElementsByClassName("table-to-colorise");
	var tablesLeft=0;
	var i=0;

	while(allTables.item(tablesLeft)){
		var allRows=allTables.item(tablesLeft).getElementsByTagName('tr');
		var rowsLeft=0;
			while(allRows.item(rowsLeft)){
				allRows.item(rowsLeft).className="first-colorised-line";
				if(allRows.item(rowsLeft+1)){allRows.item(rowsLeft+1).className="second-colorised-line";}
				rowsLeft+=2;
			}
		tablesLeft++
	}
}
window.onload=coloriseTheTable();