Question

Trying to use the following code in a page test.html:

<script language = "javascript">
function test()
{
    if (typeof a != "undefined")
    {
        document.body.innerHTML = "";
        document.write(a);
    }
    else
    {
        document.body.innerHTML = "";
        document.write("a is undefined");
    }
    var a = "a is defined";
    document.write("<br><br>");
    document.write("<a href='javascript:void(0)' onclick='function(){ test(a); }'>test</a>");
}
window.onload = function(){ test(); }
</script>

Results in the error “Uncaught SyntaxError: Unexpected token (“. How would I get the link to clear the page and display the corresponding variable?

Answer 1

The function(){ test(a); } inside your onclick is the cause of the error.

You’d need to use (function(){ test(a); }) to get a function expression instead of a function statement.

However, since a is not global and JavaScript inside an HTML on* argument won’t create a closure the code still doesn’t work.

---

Here’s a proper/working example using jQuery:

function test(a) {
    if(a !== undefined) {
        $('body').html(a);
    }
    else {
        $('body').html('a is undefined');
    }
    var a = 'a is defined';
    $('body').append('<br /><br />');
    $('<a href="#">test</a>').click(function(e) {
        e.preventDefault();
        test(a);
    }).appendTo('body');
}

$(document).ready(function() {
    test();
});