How to set required level of a control in MS Dynamics CRM 2011 using Javascript

MANDATORY:

Xrm.Page.getAttribute(YourAttributeName).setRequiredLevel(“required”);

OR

SetFieldRequiredOrRecommended(crmForm.all[YourAttributeName+ "_c"], FIELD_REQUIRED, "");

RECOMMENDED:

Xrm.Page.getAttribute(YourAttributeName).setRequiredLevel(“recommended”);

OR

SetFieldRequiredOrRecommended(crmForm.all[YourAttributeName+ "_c"], FIELD_RECOMMENDED, "");

NONE:

Xrm.Page.getAttribute(YourAttributeName).setRequiredLevel(“none”);

OR

SetFieldRequiredOrRecommended(crmForm.all[YourAttributeName+ "_c"], FIELD_NOT_REQUIRED, "");