动态函数调用仅在发出alert（）时有效

Question

I have a Javascript problem that I cannot find the answer to. Hope you can help me.

I have this element called 'scanValue', that has an onFocus and an onBlur trigger:

<input name="scanValue" class="searchFormText" style="width: 220px; font-size: 22px;" onfocus="onFocusElement(this)" onblur="onBlurElement(this)" type="text" maxLength="20" value="510210006823414"/>

If I tab out of the field the onBlurElement() function is called as expected:

function onBlurElement(object) {
        alert('onBlurElement: Start blur on ' + object.name + ' (old val = ' + prevObjectVal + ', new val = ' + object.value + ')');

        if (object.value !== prevObjectVal) {
            check(object);

            var checkFcn = 'check' + object.name;
            var fcnParms = [object.value];
            var fcn = window[checkFcn];

            alert('onBlurElement: check if ' + checkFcn + ' is a function: ' + (typeof fcn));
            if (typeof fcn == 'function') {
                alert('fcnParms length = ' + fcnParms.length + '. ToString= ' + fcnParms.toString());
                alert('fcnParms[0] length = ' + fcnParms[0].length + '. ToString= ' + fcnParms.toString());
                fcn.apply(fcn, fcnParms);
            }
        }
    }

Now this dynamic function call (fcn.apply()) should call the function 'checkscanValue(val)', but nothing happens. EXCEPT when I add an alert() to this function OR if I fire up the IE standard developer tools. In other words, if I track or debug the checkscanValue() function everything works, otherwise is does nothing. I've tried several different things, but nothing seems to work. I doubt this could have anything to do with the form being submitted with method post, but maybe someone could help me on that.

Code for the checkscanValue() function:

 function checkscanValue(val) {
        console.info('checkscanValue: start function');
        document.forms[0].airNumber.value = 'test';

        // Check if the scanned value is valid for submitting the form
        if (val[0].length === 15) {
            document.forms[0].submit();
        }
    }

Answer 1

Everything is working fine except that the "val" parameter that you are passing to the checkscanvalue function is the string that the user entered or is there by default.

So val[0] returns the first character of the string whose length can't be 15 and hence the check fails and nothing happens.

hope it helps!

Answer 2

This seems to answer my question: 'console' is undefined error for Internet Explorer

I've been using the function console.info() which is undefined if the console window of IE was never opened. This caused the function to stop. If I replaced it with an alert() it obviously worked and if I opened the console of IE, the console.info function was defined.