jquery gets the value of option and operates on option_jquery

jQuery gets the Select element, and selects the Text and Value:

Copy the code The code is as follows:

$("#select_id").change(function(){//code...}); //Add an event for Select, which is triggered when one of the items is selected
var checkText=$("# select_id").find("option:selected").text(); //Get the Text selected by Select
var checkValue=$("#select_id").val(); //Get the Value selected by Select
var checkIndex=$("#select_id ").get(0).selectedIndex; //Get the index value selected by Select
var maxIndex=$("#select_id option:last").attr("index" ); //Get the maximum index value of Select

jQuery gets the Select element and sets the Text and Value:

Instance analysis:

Copy code The code is as follows:

$("#select_id ").get(0).selectedIndex=1; //Set the Select index The item with a value of 1 is selected
$("#select_id ").val(4); // Set the Select value to 4 and the item is selected
$("#select_id option[text='jQuery'] ").attr("selected", true); //Set the Text value of Select to the jQuery item selected

jQuery adds/removes the Option item of the Select element:

Example Analysis:

Copy code The code is as follows:

$("#select_id").append( "Text"); //Append an Option (drop-down item) to Select
$("#select_id").prepend("Please select"); //Insert an Option (first position) for Select
$("#select_id option:last").remove(); //Remove from Select Option with the largest index value (the last one)
$("#select_id option[index='0']").remove(); //Delete the Option with the index value 0 in Select (the first one)
$("#select_id option[value='3']").remove(); //Delete the Option with Value='3' in Select
$("#select_id option[text='4']") .remove(); //Delete the Option with Text='4' in Select

Three-level classificationonchange="getFourthLevel()"> ;

Please select the third-level classification



Fourth level classification:


Please select a fourth-level classification

if($("#thirdLevel").val()!=0){
$("#thirdLevel option[value!=0]").remove();
}
if($("#fourthLevelId").val()!=0){
$("#fourthLevelId option[value!=0]").remove();
}//This means: If we want to select the third category: if there is data in the fourth category, delete it, if Products in the fourth category without data are default values. I will often use it after learning AJAX technology later!