应该是:
document.iframe.location.href='http://cn.search.yahoo.com/search/cn?p='+document.form1.text1.value+'&u=g&y=y'
document.iframe.location.href='http://cn.search.yahoo.com/search/cn?p='+document.form1.text1.value+'&u=g&y=y'
或document.all["iframe"].src
document.iframe.location.href="";这个语法