Integer: <input type= "text" Name= "AAA" onkeypress= "return event.keycode>=48 && event.keycode<=57 | | Event.keycode==45 "onblur=" isnum (this, ' numeric format is incorrect! ', 0) '/><br/> positive integer: <input type= "text" Name= "BBB" onkeypress = "Return event.keycode>=48 && event.keycode<=57"/><br/> real number: <input type= "text" Name= "CCC" onkeypress= "return event.keycode>=48 && event.keycode<=57 | | event.keycode==46| | Event.keycode==45 "onblur=" isnum (this, ' numeric format is incorrect! ', 0) '/><br/> positive real number: <input type= ' text ' name= ' DDD ' onkeypress = "return event.keycode>=48 && event.keycode<=57 | | Event.keycode==46 "onblur=" isnum (this, ' numeric format is incorrect! ', 0) '/><script type= ' text/javascript ' >/* determine if an object is numeric. Obj: text box, info: Error message, DefaultValue: Default value given after error */function Isnum (obj,info,defaultvalue) {if (Defaultvalue==undefi Ned) {defaultvalue=0; } if (IsNaN (Obj.value)) {//non-numeric alert (info); Obj.value=defaultvalue; Obj.focus (); } if (obj.value== "") {Obj.value=defaultvalue; Obj.focus (); }}</script>
JS numeric input control