Difference between revisions of "JQuery - Tips"
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== JQuery Tips == | == JQuery Tips == | ||
'''1. Optimize performance of complex selectors'''<br> | '''1. Optimize performance of complex selectors'''<br> |
Revision as of 11:29, 4 October 2011
<accesscontrol>Administrators,,Cem,,Maysunshine</accesscontrol>
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
}
8. Get value of question in javascript
from_Q8= "{{Q8[0].value}}";