Restricting the input field value with maxlength specified using the below javascript here,

function textLimit(field, maxlen)
{
if (field.value.length > maxlen + 1)
alert(’your input has been truncated!’);
if (field.value.length > maxlen)
field.value = field.value.substring(0, maxlen);
}

This function is called on the input text onkeyup events, like below

<INPUT TYPE=”text” NAME=”dd” onkeyup=”textLimit(dd,10)”>