leetcode 20. 有效的括号

/**
 * @param {string} s
 * @return {boolean}
 */
var isValid = function(s) {
    let tmpStack = [];
    for(let i = 0; i < s.length; i++){
        let el = s[i];
        if(el=='(' || el=='{' || el =='['){
            tmpStack.push(el);
        } else {
            if(el == ')' && tmpStack[tmpStack.length-1]=='('){
                tmpStack.pop();
            } else if (el == ']' && tmpStack[tmpStack.length-1] == '['){
                tmpStack.pop();
            } else if (el == '}' && tmpStack[tmpStack.length-1] == '{'){
                tmpStack.pop();
            } else {
                tmpStack.push(el);
            }
        }
    }
    if(tmpStack.length){
        return false;
    } else {
        return true;
    }
};