<select name="age" id="" zSelect='{
    "triggerOpt":"focus",
    "multiple":false,
    "filter":true
}'>
    <option value="a000000000000000001">a000000000000000001</option>
    <option value="a000000000000000002" selected>a000000000000000002</option>
    <option value="a000000000000000003">a000000000000000003</option>
    <option value="a000000000000000004">a000000000000000004</option>
    <option value="a000000000000000005">a000000000000000005</option>
    <option value="a000000000000000006">a000000000000000006</option>
</select>

a000000000000000001a000000000000000002a000000000000000003a000000000000000004a000000000000000005a000000000000000006

example 2

if you want set multiple default selected 
you should add a multiple attribute for select and add a selected attribute for each option
<select name="gender" id=""  zSelect='{
     "triggerOpt":"click",
     "multiple":true,
     "filter":true,
     "visibility":"visibility",
     "top":10,
     "left":400
 }' multiple>
    <option value="b00001">b000001</option>
    if you want set multiple default selected
    <option value="b00002" selected>b000002</option>
    <option value="b00003" selected>b000003</option>
    <option value="b00004" selected>b000004</option>
    <option value="b00005">b000005</option>
    <option value="b00006">b000006</option>
    <option value="b00007">b000007</option>
<select>

b000001b000002b000003b000004b000005b000006b000007

---

example 3

<select name="fname" id="" zSelect='{
"triggerOpt":"click"
}'>
    <option value="c000000000000000001">c000000000000000001</option>
    <option value="c000000000000000002">c000000000000000002</option>
    <option value="c000000000000000003">c000000000000000003</option>
    <option value="c000000000000000004">c000000000000000004</option>
    <option value="c000000000000000005">c000000000000000005</option>
    <option value="c000000000000000006">c000000000000000006</option>
</select>

c000000000000000001c000000000000000002c000000000000000003c000000000000000004c000000000000000005c000000000000000006

---

example 4

 <select name="fruit" id="fruit" zSelect='{
                     "triggerOpt":"click",
                     "multiple":true,
                     "filter":true,
                     "visibility":"visibility",
                     "top":10,
                     "left":400
                 }'>
    <option value="banana">banana</option>
    <option value="coconuts">coconuts</option>
    <option value="mango">mango</option>
    <option value="Guava">Guava</option>
    <option value="grape">grape</option>
</select>

bananacoconutsmangoGuavagrape