How to remove slds class of a tag in js controller in the Salesforce lightning component?

Hi Yogesh,

You can remove a CSS style on a component or element during runtime.
To retrieve the class name on a component, use component.find('myCmp').get('v.class'), where myCmp is the aura:idattribute value.

To remove CSS classes from a component or element, use the $ $A.util.removeClass(cmpTarget, 'class') methods.