表单脚本分析

<form action="localhost:8080" id="address" method="post">
        <select name="city" id="" type="select-one">
            <option value="beijing">北京</option>
            <option value="shanghai">上海</option>
            <option value="guangzhou">广州</option>
        </select>
</form>

var formArray = document.forms;//[form#address, address: form#address]数组
var formElement = document.forms.address;//<form></form>元素
var selectArray = document.forms.address.elements;//[select, city: select]数组
var selectElement = document.forms.address.elements.city;//<select></select>元素
var optionArray = document.forms.address.elements.city.options;//[option, option, option, selectedIndex: 0]数组