Why is my onchange function called twice when using .focus()?

Question

TLDR

• Check this example in chrome.
• Type someting and press tab. see one new box appear
• type something and pr

Answer 1

maybe this some help to anybody, for any reason, in chrome when you attach an event onchage to a input text, when you press the enterkey, the function in the event, do it twice, i solve this problem chaged the event for onkeypress and evaluate the codes, if i have an enter then do the function, cause i only wait for an enterkey user's, that not works for tab key.

    input_txt.onkeypress=function(evt){ 
            evt = evt || window.event;
            var charCode = evt.which || evt.keyCode;
            if(charCode === 13)  evaluate( n_rows ); 
             };