Question

My problem is that the else section here doesn’t seem to work.
I already surfed the web for a solution and even though there are very many questions exactly like mine, the answer always seems to be different.

This is the button I click on

<input type="submit" value="4">

I also have a button like this:

<input type="submit" id="b1" value="Back">

My Aim is to find out if the button with an ID was clicked or not.

---

var specify = "";
var prevpos = 0;

$('input[type=submit]').click(function(){
    specify = $(this).attr('value');

    if($(this).attr('id').substring(0,1) == "b")
    {
       $("html, body").animate({scrollTop: prevpos}, 777);
       $(".right").animate({opacity: 0.0}, 200);
       $(".left").animate({opacity: 1.0}, 200);
       // more stuff here                           
    }   
    else
    {
       $("html, body").animate({scrollTop: prevpos}, 777);  
       // more stuff here
    }
});

As always, any help is greatly appreciated!

Answer 1

The problem with your code is because when you click the button without an id you are calling substr() on a null, which will cause errors.

Try this instead:

var specify = "";

$('button').click(function () {
    specify = $(this).attr('value');
    var id = $(this).attr('id');

    // check there is an id, and if so see if it begins with 'b'
    if (id && id.substring(0, 1) == "b") {
        alert("You clicked the button WITH an id");
    } 
    else {
        alert("You clicked the button WITHOUT an id");
    }
});

Example fiddle