// use to select with DOM element.$("input").val();
// use the id to select the element.$("#txt_name").val();
// use type="text" with input to select the element$("input:text").val();
输入
// use to add "text content" to the DOM element.$("input").val("text content");
// use the id to add "text content" to the element.$("#txt_name").val("text content");
// use type="text" with input to add "text content" to the element$("input:text").val("text content");