window.onload 不正确

Question

This is a simple function to show the date (I don't want professional ones so this is enough). The problem is that I want to show it when the page loads. I don't want the user to press on any buttons or anything, but it's not working.

Here it is:

<script type="text/javascript">
    window.onload = ReturnDay;
</script>

<script>
    function ReturnDay() {
        var monthNames = [ 
            "January", 
            "February", 
            "March", 
            "April", 
            "May", 
            "June",
            "July", 
            "August", 
            "September", 
            "October", 
            "November", 
            "December" 
        ];
        var dayNames= [
            "Sunday",
            "Monday",
            "Tuesday",
            "Wednesday",
            "Thursday",
            "Friday",
            "Saturday"
        ];
        var newDate = new Date();

        newDate.setDate(newDate.getDate() + 1);    

        $('#dateday').html(dayNames[newDate.getDay()] + " " + newDate.getDate() + ' ' + monthNames[newDate.getMonth()] + ' ' + newDate.getFullYear());​
    }
</script>

<input id="dateday" type=text></div>

Any ideas?

Thanks a lot.

Answer 1

Function hoisting only takes place within a given <script> element. When you attempt to assign ReturnDay to onload , it doesn't exist.

Remove lines 3 and 4 of your sample code:

    </script>
     <script>

That said, assigning functions directly to event handler objects is not considered best practise. It is too easy to introduce conflicts. Use event binding instead, jQuery will abstract the differences in old-IE for you.

$(window).load(ReturnDay);

or, if you want to run the script when the DOM is ready instead of waiting for all the images in the page to load:

$(document).ready(ReturnDay);

---

Also, <input> elements are defined as EMPTY. Setting their innerHTML makes no sense. You should use val() not html() .

Answer 2

Although you could be clearer on the issue, I think the problem's because you're trying to set the html of an input field. Try this instead

$('#dateday').val(...);

Answer 3

its better to use jquery $(document).ready() instead of window.onload

Answer 4

The main problem is that you should be setting the value of the input, not it's innerHTML.

document.getElementById('dateday').value = dayNames.......;

That said, I don't think your function is defined before you try to assign it to onload. I know functions are hoisted, but I think that only applies to the current code block.

You don't need to define a named function anyway. Just do this:

window.onload = function() {
    // your date stuff here
};