原來button 沒加 type 屬性，會變成 submit @_@;
太久沒寫網頁，這個變化真大。
From the fine HTML5 specification:
A button element with no type attribute specified represents the same thing as a button element with its type attribute set to “submit”.
And a <button type="submit"> submits the form rather than behaving like a simple <button type="button"> push-button.
The HTML4 spec says the same thing:
type = submit|button|reset [CI]
This attribute declares the type of the button. Possible values:
submit: Creates a submit button. This is the default value.reset: Creates a reset button.button: Creates a push button.
So your <button> elements:
<button class="btn">Button_1</button>
<button class="btn">Button_2</button>are the same as these (in compliant browsers):
<button type="submit" class="btn">Button_1</button>
<button type="submit" class="btn">Button_2</button>and any time you hit one of those buttons you’ll submit your form.
The solution is to use plain buttons:
<button type="button" class="btn">Button_1</button>
<button type="button" class="btn">Button_2</button>Some versions of IE default to type="button" despite what the standard says. You should always specify the type attribute when using a <button> just to be sure that you will get the behavior you’re expecting.
