JSFiddle - React, Tailwind, and code Playground
HTML
<select name="plot_no" id="plot_no" class="dropdown validate_B" >
<option value="">Select no. of Plots to book</option>
<option value="1">
1 </option>
<option value="2">
2 </option>
<option value="3">
3 </option>
<option value="4">
4 </option>
</select>
</div>
<div class="marginbtm5">
<div id="divplot1" style="display:block;">
<select name="plot_no1" id="plot_no1" >
<option value="">Plot No.</option>
</select>
</div>
<div id="divplot2" style="display:none;">
<select name="plot_no2" id="plot_no2" >
<option value="">Plot No.</option>
</select>
</div>
<div id="divplot3" style="display:none; ">
<select name="plot_no3" id="plot_no3" >
<option value="">Plot No.</option>
</select>
</div>
<div id="divplot4" style="display:none;">
<select name="plot_no4" id="plot_no4" >
<option value="">Plot No.</option>
</select>
</div>
JavaScript
$("#plot_no").change(function(e)
{
var id=$(this).val();
console.log(id);
if (id =='2'){
$('#divplot2').show();
$('#divplot3,#divplot4').hide();
}
if (id=='3'){
$('#divplot2,#divplot3').show();
$('#divplot4').hide();
}
if (id=='4'){
$('#divplot2,#divplot3,#divplot4').show();
}
});