js input 只能輸入數字

HTML網頁上這么寫

<input type="text" style="ime-mode:disabled;" onpaste="return false;" onkeypress="keyPress()" />

 

function keyPress() {
var keycode = event.keyCode;
if ((keycode >= 48) && (keycode <= 57)) {
event.returnValue = true;
} else {
event.returnValue = false;
}
};