Getting the index of a selected item in table!!!!!!!!!!

when using the following code I keep getting a value of -1 for index, despite having a different item selected each time. Any reason why this is happening??????

var index = obj.getSelectionProperty("index");
document.write(index);

Yes it seems your try to get the index of the selection who are not selected yet ;)

Use this :
var index = src.getProperty("item/index"); 

sorry :

var index = this.getProperty("item/index");