Text Box style problem

We have a text box in a web page, which is used to modify the ip address. The text box style changes to the second box after editing the content in 开发者_Python百科it. How can I change the style back to the style of the first text box? We are using javascript in the client side. The web client is Internet Explorer 7.

The code snippet in ASP page which creates the text box is given below

<td style="height: 27px"><input type="text" id="txtIpAddressHost" name="txtIpAddressHost" value="" onchange="ValidateParameter(this);" onkeydown="this.style.backgroundColor='white'"  disabled="disabled" maxlength="15" /></td>

The html before and after the changes are given below

Before Keypress

<input type="text" onkeydown="this.style.backgroundColor='white'" onchange="Validate(this);" maxlength="10" value="-30.000000" name="txtCoolSetPointCkt1" id="txtCoolSetPointCkt1">

After Keypress

<input type="text" onkeydown="this.style.backgroundColor='white'" onchange="Validate(this);" maxlength="10" value="-30.000000" name="txtCoolSetPointCkt1" id="txtCoolSetPointCkt1" style="background-color: white;">

css change

css change
{

    background-color: white;

}

with CSS 2 you can achieve this only with CSS. Lets assume textbox has class ip-box.

    input.ip-box { border:1px solid #333; }
    //and when the input box has focus repeat the above rule
    input.ip-box:focus { border:1px solid #333; }

But ie7 doesn't support this pseudo class. In that case you can do with javascript like

    <input type="text" value="10.0.0.88" onfocus="javascript:this.style.border='1px solid #333' "/>