如何从 javascript 到 php 获取数据库和 js 下拉行为的值

Question

I Have created a 2 drop-down bar. 1)for selecting the floor. 2) depend on 1st drop-downbar[dynamically changed]

dropdown 1 code

 <select class="custom-select" id="selectFloor" name="selectFloor" onChange="changecat(this.value),getflatvalue();"> <option disabled="true" selected>Select floor</option> <option value="floor_0"> Floor-0 </option> <option value="floor_1"> Floor-1 </option> <option value="floor_2"> Floor-2 </option> </select>

dropdown 2 code Using JAVASCRIPT

 <script type="text/javascript"> var floorByCategory = { floor_0: ["Flat-1", "Flat-2", "Flat-3", "Flat-4"], floor_1: ["Flat-5", "Flat-6", "Flat-7", "Flat-8"], floor_2: ["Flat-9", "Flat-10", "Flat-11", "Flat-12"] } function changecat(value) { if (value.length == 0) document.getElementById("category").innerHTML = "<option></option>"; else { var catOptions = ""; for (categoryId in floorByCategory[value]) { catOptions += "<option>" + floorByCategory[value][categoryId] + "</option>"; } document.getElementById("category").innerHTML = catOptions; } } **getflatvalue(); code for this function** function getflatvalue()//taking selected value of floor Option bar. { var flatval=document.getElementById("selectFloor").value; console.log(flatval); }

Que-1: Now how i will take the value of selected value of Floor and Block in php ? I need the value of both variable to use in my db.

Que-2:Suppose i press submit button with some value and then were some error occur,then i come back to this page dropdown-1 is continued with previous selected value but dropdown-2 does not show value acccording to dropdown-1.

After submit-->error occure -->return to the same page. That does not show the flat dropdown[dropdown-2]

Answer 1

Maybe the problem lies with php variable that is used for firing the query for insertion process, check for SQL datatype & values you are inserting.

Answer 2

I set an Enum data type for some of my columns. by correcting that I can insert data through PHP.

 var floorByCategory = { 0: ["1", "2", "3", "4"], 1: ["5", "6", "7", "8"], 2: ["9", "10", "11", "12"] }

 <select class="custom-select" id="selectFloor" name="selectFloor" onChange="changecat(this.value),getflatvalue();"> <option disabled="true" selected>Select floor</option> <option value="0"> Floor-0 </option> <option value="1"> Floor-1 </option> <option value="2"> Floor-2 </option> </select>

I need to set floor and flat value like this.as per my "enum" data type. by correcting the values value can be insert.

Answer 3

After correcting this question-2 is also solved... Now the floor and flat both value are reset, and we need to select both manually.