// scripts is true for back-compat
// Intentionally let the error be thrown if parseHTML is not present
jQuery.merge( this, jQuery.parseHTML(
match[1],
context && context.nodeType ? context.ownerDocument || context : document,
true
) );
// HANDLE: $(html, props)
if ( rsingleTag.test( match[1] ) && jQuery.isPlainObject( context ) ) {
for ( match in context ) {
// Properties of context are called as methods if possible
if ( jQuery.isFunction( this[ match ] ) ) {
this[ match ]( context[ match ] );
// ...and otherwise set as attributes
} else {
this.attr( match, context[ match ] );
}
}
}
return this;
// HANDLE: $(#id)
} else {
elem = document.getElementById( match[2] );
// Check parentNode to catch when Blackberry 4.6 returns
// nodes that are no longer in the document #6963
if ( elem && elem.parentNode ) {
// Handle the case where IE and Opera return items
// by name instead of ID
if ( elem.id !== match[2] ) {
return rootjQuery.find( selector );
}
// Otherwise, we inject the element directly into the jQuery object
this.length = 1;
this[0] = elem;
}
this.context = document;
this.selector = selector;
return this;
}
// HANDLE: $(expr, $(...))
} else if ( !context || context.jquery ) {
return ( context || rootjQuery ).find( selector );
// HANDLE: $(expr, context)
// (which is just equivalent to: $(context).find(expr)
} else {
return this.constructor( context ).find( selector );
}
// HANDLE: $(DOMElement)
} else if ( selector.nodeType ) {
this.context = this[0] = selector;
this.length = 1;
return this;
// HANDLE: $(function)
// Shortcut for document ready
} else if ( jQuery.isFunction( selector ) ) {
return typeof rootjQuery.ready !== "undefined" ?
rootjQuery.ready( selector ) :
// Execute immediately if ready is not present
selector( jQuery );
}
if ( selector.selector !== undefined ) {
this.selector = selector.selector;
this.context = selector.context;
}
return jQuery.makeArray( selector, this );
}
基于jQuery(1.11.3) 2776行处，该方法比较长，我就来大概说一下我对这个方法的了解：这里主要就是做了先对selector的判断，在判断完后，查找context如果存在就继续做对有context存在情况的处理，没有则进行没有context情况的处理，而方式1和方式3：
1.$(‘.parent .child');
3.$(‘.child','.parent');他们都要进入相同的判断步骤，即上面简要说明的判断流程，等到1和3判断完后所花费的时间基本差不多，但是1内部的选择器还需要花费时间去进行sizzle相关查找，得出：
方式1.
