settimeout giving Uncaught ReferenceError: function is not defined

Question

Could somebody tell me why this gives an error?

I moved the code into functions to allow me to delay it so it's not so sensitive (was getting annoying)

Uncaught ReferenceError: hideleftnav is not defined

Uncaught ReferenceError: showleftnav is not defined

 function showleftnav()
    {
        $(".leftnavdiv").css('width','500px');
        $("body").css('padding-left','510px');
        //get measurements of window
        var myWidth = 0, myHeight = 0;
        if( typeof( window.innerWidth ) == 'number' ) {
            //Non-IE
            myWidth = window.innerWidth;
            myHeight = window.innerHeight;
        } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
            //IE 6+ in 'standards compliant mode'
            myWidth = document.documentElement.clientWidth;
            myHeight = document.documentElement.clientHeight;
        } else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
            //IE 4 compatible
            myWidth = document.body.clientWidth;
            myHeight = document.body.clientHeight;
        }
        $('#maindiv').width(myWidth - 540);
    } 

    function hideleftnav()
    {
        $(".leftnavdiv").width(10);
        $("body").css('padding-left','20px');
        //get measurements of window
        var myWidth = 0, myHeight = 0;
        if( typeof( window.innerWidth ) == 'number' ) {
            //Non-IE
            myWidth = window.innerWidth;
            myHeight = window.innerHeight;
        } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
            //IE 6+ in 'standards compliant mode'
            myWidth = document.documentElement.clientWidth;
            myHeight = document.documentElement.clientHeight;
        } else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
            //IE 4 compatible
            myWidth = document.body.clientWidth;
            myHeight = document.body.clientHeight;
        }
        $('#maindiv').width(myWidth - 50);
    }

    $(".leftnavdiv").live({                                          //code for autohide
        mouseenter:
        function () {
            setTimeout("showleftnav()", 5000);
        },
        mouseleave:
        function () {
            setTimeout("hideleftnav()", 5000);
        }
    });

Answer 1

Looks like you've found one problem with using setTimeout with a string as the first argument. Here's a condensed example illustrating the same problem:

(function() {
    function test() {
        console.log('test');
    }

    setTimeout('test()', 500);  // ReferenceError: test is not defined
    setTimeout(test, 500);      // "test"
    setTimeout(function() {     // "test"
        test();
    }), 500);
})();

Demo: http://jsfiddle.net/mXeMc/1/

Using the string causes your code to be evaluated with the window context. But since your code is in a callback function, test isn't accessible from window; it's private and restricted only to the scope of the anonymous function.

Referencing the function with just test avoids this problem because you're pointing directly to the function without using eval.