Question

I have a TextBox on my ASP.NET webpage, where the user can enter a number. What I want to do is as soon as the user moves the focus off that TextBox, to call a piece of JS to pad that number with up to 10 leading zero’s if necessary.

I’ve tried a few things but my JavaScript’s a bit rusty. Any ideas?

Answer 1

In Page_Load add “onblur” attribute to the TextBox and call javascript method to append zeros if required. This is how to do this:

javascript:

function pad(obj, length) {
    var text = obj.value;
    var str = '' + text;
    while (str.length < length) {
        str = '0' + str;
    }

    obj.value = str;

}

Code behind

protected void Page_Load(...)
{
    textBox.Attributes("onblur", "javascript:pad(this, 10);");
}