Can somebody tell me what I am doing wrong?

```
window.onload = initForm;
function initForm() {
    var allTags = document.getElementsByTagName("*");
    for(i=0; i<allTags.length; i++) {
        if (allTags[i].className.indexOf("textbox") > -1) {
            allTags[i].onFocus = fieldSelect;
            allTags[i].onBlur = fieldDeSelect;          
        }
    }
}
function fieldSelect() {
    this.style.backgroundImage = "url('inputBackSelected.png')";
}

function fieldDeSelect() {
    this.style.backgroundImage = "url('inputBack.png')";
}

```

I am a beginner at JavaScript so I am not used to debugging code yet.

Thanks

Luke