javascript - get all selected values from ListBox (client side) -


i'm trying implement custom validator in javascript vb.net page. validator should check if in multichoice listbox there aren't selected values, showing error pop if so.

the thing is, want client side, in 'validatefunction' function last selected (or unselected, if selected already) item. know how in code-behind code, want client-side.

aspx code:

 <asp:listbox id="lbedit" runat="server" selectionmode="multiple">  </asp:listbox>  <asp:customvalidator id="cvedit" runat="server" display="none" controltovalidate="lbedit" clientvalidationfunction="validatefunction"/>  <ajax:validatorcalloutextender runat="server" id="vceedit" targetcontrolid="cvedit" />

javascript code:

 function validatefunction(source, arguments) {         var options = document.getelementbyid(source.controltovalidate).options;             (var = 0; < options.length; i++) {                 if (options[i].selected == true) {                     args.isvalid = true;                     return;                 }             }             args.isvalid = false;  }

as said, since last (un)selected item 1 selected in 'options' array, validating function return true...

i thought of populating array in javascript function 'true selected array' , compare values selected option each time function fires.. think there should better way.

so... there straight forward way selected items multichoice listbox in javascript?

your question bit unclear, , function seems working, answer here last part of question so... there straight forward way selected items multichoice listbox in javascript?

try js function

<script type="text/javascript">         function validatefunction() {             var options = document.getelementbyid('<% = this.lbedit.clientid %>').options;             var selecteditems;             (var = 0; < options.length; i++) {                 if (options[i].selected == true) {                     if (selecteditems) {                         selecteditems = selecteditems + ";" + options[i].value;                     }                     else {                         selecteditems = options[i].value;                     }                 }             }             if (selecteditems) {                 alert(selecteditems);                 return true;             }             else {                 alert("no item selected");                 return false;             }         }     </script>

and aspx code, removed validator

 <asp:listbox id="lbedit" runat="server" selectionmode="multiple" >  </asp:listbox>     <asp:button id="test" runat="server" text="send"  onclientclick="return validatefunction();"/>

in developer tools of browser can see detailed information properties of object

enter image description here


Comments

Post a Comment

Popular posts from this blog

Sort a complex associative array in PHP -

this question has answer here: php sort array subarray value 5 answers i have associative array in php like: $newarray1 = array ( [producta] => array ( [link] => http://sanjosespartan.com/blog/products/agile-java-development/ [visitcount] => 4 ) [productd] => array ( [link] => http://sanjosespartan.com/blog/products/intro-to-go/ [visitcount] => 1 ) [productg] => array ( [link] => http://sanjosespartan.com/blog/products/node-js-for-developers/ [visitcount] => 1 ) [productb] => array ( [link] => http://sanjosespartan.com/blog/products/beginning-mysql/ [visitcount] => 1 ) [productc] => array ( [link] => http://sanjosespartan.com/blog/products/computer-networks/ [visitcount] => 1 ) ...
Read more

vb.net - How to ignore if a cell is empty nothing -

how use roscolor() ignore value (like empty cell) ? color row if value upper 5 when there nothing in cell, want ignore roscolor() apply, how? public sub roscolor() integer = 0 quotedatagridview1.rows.count() - 1 step +1 dim val integer val = quotedatagridview1.rows(i).cells(3).value if val = vbempty quotedatagridview1.rows(i).defaultcellstyle.backcolor = color.white elseif val < 5 quotedatagridview1.rows(i).defaultcellstyle.backcolor = color.red elseif val > 5 , val < 10 quotedatagridview1.rows(i).defaultcellstyle.backcolor = color.lightyellow end if next end sub you can check empty value following public sub roscolor() integer = 0 quotedatagridview1.rows.count() - 1 step +1 dim val = quotedatagridview1.rows(i).cells(3).value if isdbnull(val) or val nothing quotedatagridview1.rows(i).defaultcellstyle.backcolor = color.white ...
Read more

recursion - Can every recursive algorithm be improved with dynamic programming? -

i first year undergraduate csc student looking competitive programming. recursion involves defining , solving sub problems. understand, top down dynamic programming (dp) involves memoizing solutions sub problems reduce time complexity of algorithm. can top down dp used improve efficiency of every recursive algorithm overlapping sub problems? dp fail work , how can identify this? the short answer is: yes. however, there constraints. obvious 1 recursive calls must overlap. i.e. during execution of algorithm, recursive function must called multiple times same parameters. lets truncate recursion tree memoization. can use memoization reduce number of calls. however, reduction of calls comes price. need store results somewhere. next obvious constraint need have enough memory. comes not-so obvious constraint. memory access requires time. first need find result stored , maybe copy location. in cases, might faster let recursion calculate result instead of loading somewher...
Read more