CSSStyleSheet.insertRule()

 
概述

insertRule方法用来给当前样式表插入新的样式规则.

语法

stylesheet.insertRule(rule, index)

参数

  • rule是一个字符串,包含了要插入的样式规则(选择器和样式声明).
  • index是一个数字,表示了要插入的位置.

示例1

 // 在样式表的最顶处插入一个新规则
 myStyle.insertRule("#blanc { color: white }", 0); 

示例2

/**
 * Add a stylesheet rule to the document (may be better practice, however,
 *  to dynamically change classes, so style information can be kept in
 *  genuine styesheets (and avoid adding extra elements to the DOM))
 * Note that an array is needed for declarations and rules since ECMAScript does
 * not afford a predictable object iteration order and since CSS is 
 * order-dependent (i.e., it is cascading); those without need of
 * cascading rules could build a more accessor-friendly object-based API.
 * @param {Array} decls Accepts an array of JSON-encoded declarations
 * @example
addStylesheetRules([
  ['h2', // Also accepts a second argument as an array of arrays instead
    ['color', 'red'],
    ['background-color', 'green', true] // 'true' for !important rules 
  ], 
  ['.myClass', 
    ['background-color', 'yellow']
  ]
]);
 */
function addStylesheetRules (decls) {
    var style = document.createElement('style');
    document.getElementsByTagName('head')[0].appendChild(style);
    if (!window.createPopup) { /* For Safari */
       style.appendChild(document.createTextNode(''));
    }
    var s = document.styleSheets[document.styleSheets.length - 1];
    for (var i=0, dl = decls.length; i < dl; i++) {
        var j = 1, decl = decls[i], selector = decl[0], rulesStr = '';
        if (Object.prototype.toString.call(decl[1][0]) === '[object Array]') {
            decl = decl[1];
            j = 0;
        }
        for (var rl=decl.length; j < rl; j++) {
            var rule = decl[j];
            rulesStr += rule[0] + ':' + rule[1] + (rule[2] ? ' !important' : '') + ';\n';
        }

        if (s.insertRule) {
            s.insertRule(selector + '{' + rulesStr + '}', s.cssRules.length);
        }
        else { /* IE */
            s.addRule(selector, rulesStr, -1);
        }
    }
}

附注

对于普通样式规则来说,要插入的字符串应该包含选择器和样式声明.对于@规则来说,要插入的字符串应该包含@标识符和样式规则的内容.

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 此页面的贡献者: teoli, arunpandianp, ziyunfei
 最后编辑者: teoli,