If you mean to change the text based on for example a status, you must create a variable like this in your Custom JS:
var myCustomTooltipVariable = "Original text";
Then create a rule to trigger on change of the field you want to use to change the tooltip text, and set it to call the custom function in your Custom JS. Set up the function like this:
function changeMyTooltip(){
var status = getFieldValue("Status");
switch(status){
case "Not started":
myCustomTooltipVariable = "A tooltip text suited for this status";
break;
case "In progress":
myCustomTooltipVariable = "A tooltip text suited for this status";
break;
}
}
This will update the tooltip text based on the columne named “Status”. Use the variable in the tooltip textarea like described in the comment above (keep in mind the single whitespace before the first curly brace).
Use this as a starting point and let me know if you have any questions.
Alexander