button与submit_html/css_WEB-ITnose

Original text from:

http://blog.sina.com.cn/s/blog_693d183d0100uolj.html

Submit is a special case of button and a type of button. It automatically integrates the action of submission.

If the form needs to be processed with JS (including input verification) after clicking the submit button before submitting it, you usually have to change submit to button, that is, cancel its automatic submission behavior. Otherwise, it will cause The effect of submitting twice, for dynamic web pages, is to operate the database twice. Or add return true or false when verifying when using submit.

Submit and button are both displayed in the form of buttons. They both look like buttons. The difference is in the type attribute and the event that is sent in response. Submit will submit the form, but button will not submit the form.

The main difference between the two is:

Submit defaults to form submission, which can submit the form (form).

Button responds to user-defined events, if onclick is not specified Waiting for the event handler function, it does not do anything. Of course, the button can also complete the work of form submission.

INPUT type=submit That is, send the form and press Enter to submit the form

INPUT type =button is a simple button function, and what is submitted is innerTEXT

================Detailed comparison between submit and button=========== ========================

submit: a special button that will automatically submit the form data. If the onClick method does not add return, it will Automatic submission will not act as a constraint.

Therefore, if you need to verify when using submit, please add return true or false.

Example: , when judging in JS, write return true; or return false;

button: an ordinary button, which will not be automatically submitted. Form data can be submitted explicitly in JS: document.form1.submit(). Usage occasions: There are multiple submit buttons on a page. It needs to be determined according to the user's operation which controller is submitted to. In this case, just It is necessary to determine the user's operation in JS, then assign a value to document.form1.action based on the operation and submit document.form1.submit()

============== =What to do if you want to handle all submissions in a servlet==================

The submit button is also an HTML component, so it is also It can be obtained through getParameter(), then the parameters of getParameter() also need to be fixed

The parameter is the name of the submit button of all forms. Of course, the name of the submit button must be the same to be unified in one servlet according to the submission The value of the button to distinguish the operation

====================== About the path settings ============ =======================

A. Write the path directly in the page, such as href="jsp/a.html" means plain Access to the level directory. This example means that there is a JSP folder in the level directory, and the a.html file in the folder is accessed

B. Write the path directly in JAVA, such as response.sendRedirect(" jsp/a.jsp") means that there is a JSP folder in the project root directory, and the a.jsp file in the folder is accessed

C. If you find that the address bar in the browser is incorrect with the above settings , you can write the absolute path: /project name/folder name/file name

However, people who are engaged in WEB UI should note that using submit to improve the usability of the page:

After using submit, the page supports the keyboard enter key operation, but many WEB software designers may not have noticed that submit is unified.

After using button, the page often does not support the enter key. Therefore, if you need to support the enter key, you must set up a submit. By default, the enter key operates on the first submit on the page.

After executing onClick, go to action. Automatic submission does not require onClick, so onclick is not required here.

After onClick is executed, the jump file is in the js file Control, submission requires onClick. If there is no onClick

For example:

type="submit"

" method="post" onSubmit="return check_submit(this)">

type="button"

" method="post" name="frmAddModi" >