How to call java script on button click event which handles event to add new row?

I have a button which adds new row in grid view at button click event. A row contains two text boxes and two drop down lists. But before adding new row I 开发者_StackOverflow中文版want to check if all controls in the first rows are filled or not. so for that I want to call java script on button click event. So how can I call java script on button which already handles an event new row in grid view?

You can define a javascript function which will check if all controls are filled and then if the requirements are accomplished to add a new row.

Ex:

function example()
{
  if(controls filled)
add a new row;
}

then

<button type="button" onclick="example()">Click Me!</button>

The solution is to chain the calls. There are two ways to do this:

1. You can use the onclick property of the button in your function definition:

   function chainOnClick(button, func) {
       var origFunc = button.onclick;
       var tmp = function(e) {
           if(func(e)) {
                return origFunc(e);
           }
           return false;
       }
       button.onclick = tmp;
   }
   

   Note that I've found that unreliable if there is no onclick installed; for some reason, the pattern doesn't work with the browser's default "onclick" handler.

2. You can move the code that handles the click into a function (which you probably already have). Now you write a validation function and install this new click handler:

   function validatedOnClick(e) {
       if(validateLastRow(e)) {
            return originalClickHandler(e);
       }
       return false;
   }