changing element value with event onkeyup() javascript

Question

Please help me with my script. I don't understand why my script does not working :(

    <html>
    <body>
    <input type="text" id="input" onkeypress="myFunction()">
    <input type="button" value="Hallo" id="but">
    <script>
    function myFunction{
        document.getElementById('but').value = "changed";
    }
    </script>
    </body>
    </html>

@edgar-p-yan. It's nice to get into the habit of setting break-points or at least do some `console.log("inside function")` so that you can see at which stage the code if failing. The output is shown in the console (in Chrome you can access it by pressing CTRL + SHIFT + I and switching to the Console tab. There you can also see any error message, and they may indicate where/what your error is. — jonahe, Aug 23 '17 at 18:49

score 1 · Accepted Answer · answered Aug 23 '17 at 18:51

1

Very simple you have forgotten to place parantheses after myFunction.

your code should be:

 <script>
function myFunction(){
    document.getElementById('but').value = "changed";
}
</script>

answered Aug 23 '17 at 18:51

Sadhon

674
7
11

score 0 · Answer 2 · answered Aug 23 '17 at 18:45

This way it work. Function needs parenthesis

    function myFunction() {
        document.getElementById('but').value = "changed";
    }

<html>
    <body>
    <input type="text" id="input" onkeypress="myFunction()">
    <input type="button" value="Hallo" id="but">

    </body>
    </html>

an alternative way is

    myFunction = function () {
        document.getElementById('but').value = "changed";
    }

changing element value with event onkeyup() javascript

2 Answers2