รบกวนพี่ๆ ผู้รู้ ช่วยหนูหน่อยนะ คิดว่าน่าจะเกี่ยวกับjava script ค่ะ

<script type="text/javascript">
    function TxtLength(txtBox) {
        var barFrame = document.getElementById('barFrame');

        if (txtBox.value.substr(0, 7).toLowerCase() == 'keyword') {
            txtBox.value = txtBox.value.substr(0, 45)
            barFrame.style.width = 45;
        }
        else {
            txtBox.value = txtBox.value.substr(0, 35)
            barFrame.style.width = 35;
        }

        var barChart = document.getElementById('barchart');
        barChart.style.width = txtBox.value.length;
    }               
</script>

<div style="position: relative;">
    <div style="position: absolute; top: 0px; left: 0px;">
        <input type="text" size="40" onkeyup="javascript:TxtLength(this);" />      
    </div>
    <div id="barFrame" style="position: absolute; top: 3px; left: 270px; height: 10px; border: solid 1px black; width: 35px; padding: 2px;">
        <div id="barchart" style="height: 10px; width: 0px; background: blue;"></div>
    </div>
</div>