Common Operations on select drop-down boxes in js

This article summarizes the implementation code of common operations on the select drop-down box in jquery and javascript. If you need to know it, you can refer to it.

Js select and option operations
1. dynamically create select

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Function createSelect (){ Var mySelect = document. createElement_x ("select "); MySelect. id = "mySelect "; Document. body. appendChild (mySelect ); }

2. Add option

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Function addOption (){ // Search for objects by id, Var obj = document. getElementByIdx_x ('myselect '); // Add an option Obj. add (new Option ("text", "value"); // This can only be valid in IE Obj. options. add (new Option ("text", "value"); // compatible with IE and firefox }

3. Delete All option options

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Function removeAll (){ Var obj = document. getElementByIdx_x ('myselect '); Obj. options. length = 0; }

4. delete an option

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Function removeOne (){ Var obj = document. getElementByIdx_x ('myselect '); // Index. The sequence number of the option to be deleted. The sequence number of the selected option is used here. Var index = obj. selectedIndex; Obj. options. remove (index ); }

5. Obtain the option value.

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Var obj = document. getElementByIdx_x ('myselect '); Var index = obj. selectedIndex; // the serial number of the selected option. Var val = obj. options [index]. value;

6. Obtain the option text

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Var obj = document. getElementByIdx_x ('myselect '); Var index = obj. selectedIndex; // the serial number of the selected option. Var val = obj. options [index]. text;

7. Modify option

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Var obj = document. getElementByIdx_x ('myselect '); Var index = obj. selectedIndex; // the serial number of the selected option. Var val = obj. options [index] = new Option ("new text", "new Value ");

8. Delete select

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Function removeSelect (){ Var mySelect = document. getElementByIdx_x ("mySelect "); MySelect. parentNode. removeChild (mySelect ); }

Next, let's send the jquery + select/"target =" _ blank "> jquery select operation.
Syntax explanation:

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1. $ ("# select_id"). change (function () {// code...}); // Add an event for Select, triggered when one of the Select events is selected 2. var checkText = $ ("# select_id"). find ("option: selected"). text (); // obtain the selected Text 3. var checkValue = $ ("# select_id"). val (); // obtain the Value selected by Select 4. var checkIndex = $ ("# select_id"). get (0). selectedIndex; // obtain the index value selected by Select 5. var maxIndex = $ ("# select_id option: last"). attr ("index"); // obtain the largest index value of Select.

JQuery sets the Text and Value selected by Select:

Syntax explanation:

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1. $ ("# select_id"). get (0). selectedIndex = 1; // Select an item whose Select index value is 1 2. $ ("# select_id"). val (4); // Select an item whose Value is set to 4. 3. $ ("# select_id option [text = 'jquery ']"). attr ("selected", true); // set the Select Text value to jQuery.

JQuery adds/deletes Select Option items:
Syntax explanation:

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1. $ ("# select_id"). append ("Text"); // append an Option for Select (drop-down) 2. $ ("# select_id"). prepend ("Select"); // insert an Option for Select (first position) 3. $ ("# select_id option: last"). remove (); // Delete the largest Option (last) index value in Select) 4. $ ("# select_id option [index = '0']"). remove (); // Delete the Option with the index value 0 in Select (the first option) 5. $ ("# select_id option [value = '3']"). remove (); // Delete the Option with Value = '3' In the Select statement 5. $ ("# select_id option [text = '4']"). remove (); // Delete the Option of '4' Text = '4' in Select