INPUT type=image 自动提交表单

today when i write the system logon code,i write the code like : ; so the confusing thing come,when i click the image the form is automatically submit; so the above code submit the form twice. i check the html conference, i find a sentence like this: "INPUT type=image 创建一个图像控件，该控件单击后将导致表单立即被提交。" that is to say:Creates an image control that, when clicked, causes the form to be immediately submitted. so you can write the logon code like below formats: 1. 2.; when you write the code like the second fomat,you must set the action to the form before the image is clicked.