创建html option的两种方法

dom api创建法 和  js 构造函数创建法 

http://www.javascriptkit.com/javatutors/selectcontent.shtml

http://www.w3schools.com/jsref/dom_obj_option.asp

 

Create an Option Object

You can create an <option> element by using the document.createElement() method:

var x = document.createElement("OPTION");

 

 

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new Option(text, value, defaultSelected, selected)