设直线l：x=my+n①与抛物线y^2=2px(p>0)②相交于A(x1,y1),B(x2,y2),
把①代入②，y^2-2mpy-2np=0,
y1+y2=2mp,y1y2=-2np,
由①，x1x2=(my1+n)(my2+n)=m^2y1y2+mn(y1+y2)+n^2,
OA⊥OB,
∴0=x1x2+y1y2=(m^2+1)y1y2+mn(y1+y2)+n^2,
=-2np(m^2+1)+2m^2np+n^2
=n^2-2np,
解得n=0或2p,
∴直线l与x轴的交点为(0,0)或(2p,0).