Book: "Pro JavaScript techniques proficient in JavaScript" simple Dom Traversal

// Find the function of the previous sibling element of the relevant element

Function Prev (ELEM ){

Do {

ELEM = ELEM. previussibling;

} While (ELEM & ELEM. nodetype! = 1 );

Return ELEM;

}

// Find the function of the first child element of an element

Function first (ELEM ){

ELEM = ELEM. firstchild;

Return ELEM & ELEM. nodetype! = 1?

Next (ELEM): ELEM;

}

// Find the function of the last child element of an element

Function last (ELEM ){

ELEM = ELEM. lastchild;

Return ELEM & ELEM. nodetype! = 1?

Prev (ELEM): ELEM;

}

// Find the function of the element parent Element

Function parent (ELEM; num ){

Num = num | 1;

For (VAR I = 0; I <num; I ++)

If (ELEM! = NULL) ELEM = ELEM. parentnode;

Return ELEM;

}

With these new functions, you can quickly traverse Dom documents without worrying about text between elements. For example, you need to find the next element of the

// Search for the next element of the

Next (first (document. Body ))