Question

如何实现select组件的选择输入过滤作用

Answer 1

(function ( $ ) {

$.fn.editableSelect = function() {
var instanceVar;
//此this.each()指的就是对当前对象的遍历，这里的当前对象指代的就是对当前两个下拉选择框对象的一一遍历
this.each(function(){
var originalSelect = $(this);
//check if element is a select
if(originalSelect[0].tagName.toUpperCase()==="SELECT"){
//wrap the original select在原始的<select>外围插入<div></div>框
originalSelect.wrap($("<div/>"));
var wrapper = originalSelect.parent();
wrapper.css({display: "inline-block"});
//place an input which will represent the editable select
//在选择菜单上加入input输入框<input alt title ..... style="width:......" value="">
var inputSelect = $("<input/>").insertBefore(originalSelect);
//get and remove the original id
var objID = originalSelect.attr("id");
originalSelect.removeAttr("id");
//add the attributes from the original select
//input输入框的各种属性设置
inputSelect.attr({
alt: originalSelect.attr("alt"),
title: originalSelect.attr("title"),
class: originalSelect.attr("class"),
name: originalSelect.attr("name"),
disabled: originalSelect.attr("disabled"),
tabindex: originalSelect.attr("tabindex"),
id: objID
});
//get the editable css properties from the select
var rightPadding = 15;
inputSelect.css({
width: originalSelect.width()-rightPadding,
height: originalSelect.height(),
fontFamily: originalSelect.css("fontFamily"),
fontSize: originalSelect.css("fontSize"),
background: originalSelect.css("background"),
paddingRight: rightPadding
});
inputSelect.val(originalSelect.val());
//add the triangle at the right
var triangle = $("<div/>").css({
height: 0, width: 0,
borderLeft: "5px solid transparent",
borderRight: "5px solid transparent",
borderTop: "7px solid #999",
position: "relative",
top: -(inputSelect.height()/2)-5,
left: inputSelect.width()+rightPadding-10,
marginBottom: "-7px",
pointerEvents: "none"
}).insertAfter(inputSelect);
//create the selectable list that will appear when the input gets focus
//聚焦的时候加上<ol><ol/>下拉框
var selectList = $("<ol/>").css({
display: "none",
listStyleType: "none",
width: inputSelect.outerWidth()-2,
padding: 0,
margin: 0,
border: "solid 1px #ccc",
fontFamily: inputSelect.css("fontFamily"),
fontSize: inputSelect.css("fontSize"),
background: "#fff",
position: "absolute",
zIndex: 1000000
}).insertAfter(triangle);
//add options
//在resourceData变量中存储当前下拉框中的所有数据
//******
var resourceData = [];
originalSelect.children().each(function(index, value){
prepareOption($(value).text(), wrapper);
resourceData.push($(value).text());
});
//******
//bind the focus handler
//在鼠标聚焦的时候fadeIn（100），即下拉显示当前下拉框
inputSelect.focus(function(){
selectList.fadeIn(100);
//v存储的是在input输入框中输入的内容，如果输入的内容不为空，就在存储原始下拉框的所有数据中找到出现v中字符的数据压入newResourceData变量中
//******
var v = inputSelect.val();
var newResourceData = [];
if(v != "") {
$.each(resourceData, function(i, t){
if(t.indexOf(v) != -1)
newResourceData.push(t);
});
}
wrapper.children("ol").empty();
$.each(newResourceData, function(i, t){
prepareOption(t, wrapper);
});
//******
}).blur(function(){
selectList.fadeOut(100);
}).keyup(function(e){
if(e.which==13) inputSelect.trigger("blur");
//在enter快捷键按下后弹起的时候执行的事件
//******
var v = inputSelect.val();
var newResourceData = [];
if(v != "") {
$.each(resourceData, function(i, t){
if(t.indexOf(v) != -1)
newResourceData.push(t);
});
}
wrapper.children("ol").empty();
$.each(newResourceData, function(i, t){
prepareOption(t, wrapper);
});
//******
});
//hide original element
originalSelect.css({visibility: "hidden", display: "none"});

//save this instance to return it
instanceVar = inputSelect
}else{
//not a select
return false;
}
});//-end each

/** public methods **/

/**
* Adds an option to the editable select
* @param {String} value - the options value
* @returns {void}
*/
instanceVar.addOption = function(value){
prepareOption(value, instanceVar.parent());
};

/**
* Removes a specific option from the editable select
* @param {String, Number} value - the value or the index to delete
* @returns {void}
*/
instanceVar.removeOption = function(value){
switch(typeof(value)){
case "number":
instanceVar.parent().children("ol").children(":nth("+value+")").remove();
break;
case "string":
instanceVar.parent().children("ol").children().each(function(index, optionValue){
if($(optionValue).text()==value){
$(optionValue).remove();
}
});
break;
}
};

/**
* Resets the select to it's original
* @returns {void}
*/
instanceVar.restoreSelect = function(){
var originalSelect = instanceVar.parent().children("select");
var objID = instanceVar.attr("id");
instanceVar.parent().before(originalSelect);
instanceVar.parent().remove();
originalSelect.css({visibility: "visible", display: "inline-block"});
originalSelect.attr({id: objID});
};

//return the instance
return instanceVar;
};

/** private methods **/
//prepareOption函数的作用就是在当前下拉框中添加新选项
function prepareOption(value, wrapper){
var selectOption = $("<li>"+value+"</li>").appendTo(wrapper.children("ol"));
var inputSelect = wrapper.children("input");
selectOption.css({
padding: "3px",
textAlign: "left",
cursor: "pointer"
}).hover(
function(){
selectOption.css({backgroundColor: "#eee"});
},
function(){
selectOption.css({backgroundColor: "#fff"});
});
//bind click on this option
selectOption.click(function(){
inputSelect.val(selectOption.text());
inputSelect.trigger("change");
});
}

}( jQuery ));