A brief analysis of Jquery operation selection

Without further ado, please look at the code:

<select id="Select1">
  <option value="one">一</option>
  <option value="two">二</option>
  <option value="thr">三</option>
  <option value="tho">四</option>
</select>

Comments:

(1) Assign a value to the drop-down box: $("#Select1").val("二"); At this time, the option with value two has been selected. You can get the index at this time to be 1 through $("#Select1")[0].selectedIndex or $("#Select1").get(0).selectedIndex. The drop-down box The index starts from 0

(2) By setting the attribute $("#Select1 option[value='two']").attr('selected',true); you can also set the selection. In fact, Equivalent to assignment

(3) Get the text corresponding to the selected value:

      1. Get by value: $("#Select1 option[value='" + value + "']") .text() or $("#Select1").find("option[value='" + value + "']").text()

2. Obtain through the selected state: $(" #Select1").find("option:selected").text()

(4) Cascade of drop-down boxes:

Many times the cascade of select is used, that is, the second The value of each select changes with the value selected by the first select. This is very simple in jQuery.

For example: $(".selector1").change(function(){

// Clear the second one first

$(".selector2").empty ();

// In actual applications, multiple options here are generally generated using a loop

var option = $("<option>").val(1).text("pxx");
  $(".selector2").append(option);
  });

(5) Select the corresponding option through the value of the text in the option Value

var count = $("#Select1 option").length;
   for (var i = 0; i < count; i++) {
    if ($("#Select1").get(0).options[i].text == $(this).val()) {
     $("#Select1").get(0).options[i].selected = true;
     break;
    }
   }

Ps: How to remove leading and trailing spaces in jquer: $.trim(value);

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