限制只能输入数字（javascript脚本）

function Nochar()
            {
                var k=window.event.keyCode;  
                if ((k==46)||(k==8)||(k==189)||(k==109)||(k==190)||(k==110)|| (k>=48 && k<=57)||(k>=96 && k<=105)||(k>=37 && k<=40))
                {}
                else if(k==13)
                {
                    window.event.keyCode = 9;
                }
                else
                {
                    window.event.returnValue = false;
                }
            }