.length incrementation and decrementation

Question

Here's my code in javascript:

function length(inputLength){
    this.inputLength = inputLength;
    document.getElementById('view').innerHTML = inputLength.length;
}

Normally, when I press a key, a counter is incremented and when I delete a char with the backspace key, the counter is decremented. The problem is when I delete a char, the count is incremented by 1 too then is decremented normally. Try this code by using the "onkeydown" event.

Can you help me?

what is `inputLength` ??? (the parameter passed to the function) — Manse, Dec 11 '12 at 14:58
I don't really get it? If it's a text input, the length property of the value will always be the correct length (number of characters) of the string? — adeneo, Dec 11 '12 at 15:01
Your issue is that your triggering `onkeydown` try using `onkeyup` instead and see what that does. — Ryan, Dec 11 '12 at 15:02
@adeneo Normally yes. The length property count how many characters there are is the input. — mathieu_b, Dec 11 '12 at 15:02
Also, showing us how your getting inputLength would help as that may be where the problem lies. — Josh Farneman, Dec 11 '12 at 15:06

score 2 · Accepted Answer · answered Dec 11 '12 at 15:02

2

Why not simplify it and just do this :

function calcLength(elem) {
    document.getElementById('output').innerHTML = elem.value.length;
}

Where elem is the input. Using elem.value.length will get the length of the content within the input.

An example of the HTML would be this

<input id="testing" value="" onkeyup="calcLength(this)" />
Length = <span id="output"></span>

Working example here

answered Dec 11 '12 at 15:02

Manse

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It's work, thanks! The solution is to use "onkeyup" instead "onkeydown". And thanks for the simplification! – mathieu_b Dec 11 '12 at 15:04
@MathieuBrochard im not sure the answer was the `onkeyup` vs `onkeydown` it really makes no difference - its just the order of execution ... read this http://stackoverflow.com/questions/3396754/onkeypress-vs-onkeyup-and-onkeydown – Manse Dec 11 '12 at 15:07
Apparently yes, I've replaced `onkeydown` by `onkeyup` and it's works... And don't worry, I wanted to validate your answer but I must wait 6 minutes :) – mathieu_b Dec 11 '12 at 15:07

.length incrementation and decrementation

1 Answers1