JQuery - Tips

JQuery Tips

1. Optimize performance of complex selectors
var subset = $(""); $("input[value^=]", subset);

2. Set Context and improve the performance
On the core jQuery function, specify the context parameter when. Specifying the context parameter allows jQuery to start from a deeper branch in the DOM, rather than from the DOM root. Given a large enough DOM, specifying the context parameter should translate to performance gains. $("input:radio", document.forms[0]);

3. Live Event Handlers
Set an event handler for any element that matches a selector, even if it gets added to the DOM after the initial page load: $('button.someClass').live('click', someFunction);

4. To show / hide element

$("a").hide();
 $("a").show();

5. Check element exists

if ($("#someDiv").length) {}

6. Back to top button/link

$('#top').click(function() {  
 $(document).scrollTo(0,500);  }

7. Change width of item on many browser

$('#input:text[name=QUESTION.Q12.1]).width(500);

var error_message = "The error was happened" var oldCheck = questioncheck; questioncheck = function() {

  //QUESTION.Label1
  if (checkLength("QUESTION.Label1",5)){
     ErrorMessages.getInstance().clearErrorMessages();
     ErrorMessages.getInstance().showErrorMessage(error_message);
     return;
  }
  

}

function checkLength(objname,maxlength) {

  var ao=$("input:text[name="+objname+"]");
  if (ao.val().length>maxlength)
     return true;
  return false

}

7. Get value of question in javascript
from_Q8= "{{Q8[0].value}}";