js restricts the text box to only input numbers (regular expression)_form effects

function chkPrice(obj){
obj.value = obj.value.replace(/[^d.]/g,"");
//Must ensure that the first digit is a number instead.
obj.value = obj.value.replace(/^ ./g,"");
//Guarantee that only one appears, not multiple.
obj.value = obj.value.replace(/.{2,}/g,".");
//Guaranteed. It will only appear once and not more than twice
obj.value = obj.value.replace(".","$#$").replace(/./g,"" ).replace("$#$",".");
}
function chkLast(obj){
// If illegal characters appear, intercept them
if(obj.value.substr ((obj.value.length - 1), 1) == '.')
obj.value = obj.value.substr(0,(obj.value.length - 1));
}