javascript - Get value using a function return

Question

I am trying to write a simple function to avoid replication of code and return a value from an input but when I try to return it via the function i just get "undefined".

Any ideas why?

function get_selected_id() {
    return $(this).parents("tr").find("input[name*=page_id]").val();
}

$("a").click( function(e) {
    e.preventDefault();
    alert(get_selected_id()); // RETURNS UNDEFINED
    alert($(this).parents("tr").find("input[name*=page_id]").val()); // RETURNS 123
});

html (very simplified):

<table>
    <tr>
        <td>page id <input type="hidden" value="123" name="page_id[]" /></td>
        <td><a href="#">Click</a></td>
    </tr>
</table>

Tom · Accepted Answer · 2014-02-28 10:46:49Z

1

You don't pass the value to get_selected_id(). So when the function tries to return $(this) it is undefined because it can't match any element. You have to pass as argument the element that is clicked!

Try

function get_selected_id(e) {
    return e.parents("tr").find("input[name*=page_id]").val();
}

$("a").click( function(e) {
    e.preventDefault();
    alert(get_selected_id($(this))); // RETURNS 123
    alert($(this).parents("tr").find("input[name*=page_id]").val()); // RETURNS 123
});

DEMO

edited Feb 28, 2014 at 10:46

Tom

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answered Feb 28, 2014 at 10:42

laaposto

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Comments

zealot · Accepted Answer · 2014-02-28 10:42:31Z

0

this keyword in javascript is context-dependent.

Try to pass $(this) as argument to your function:

function get_selected_id(obj) {
    return obj.parents("tr").find("input[name*=page_id]").val();
}

alert(get_selected_id($(this)));

answered Feb 28, 2014 at 10:42

zealot

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