js禁止空格的输入

/**禁止空格输入 onkeydown="return banInputSapce(event);"**/
function banInputSapce(e)
{
var keynum;
if(window.event){
keynum = e.keyCode
}else if(e.which){
keynum = e.which
}if(keynum == 32){
return false;
}
return true;
}