Today, when I was working on a project, I encountered a problem. I needed to show multiple checkbox checkbox check boxes, but only allowed to select up to 6. After debugging for a long time, it finally came out, the code is as follows:
<SCRIPT LANGUAGE="JavaScript"> var c=0,limit=6; function doCheck(obj) { obj.checked?c++:c--; if(c>limit){ obj.checked=false; alert("over"); c--; } } </SCRIPT> <html> <body> <input type="CHECKBOX" name="sample1" onClick="doCheck(this)">A <input type="CHECKBOX" name="sample2" onClick="doCheck(this)">B <input type="CHECKBOX" name="sample3" onClick="doCheck(this)">C <input type="CHECKBOX" name="sample4" onClick="doCheck(this)">D <input type="CHECKBOX" name="sample5" onClick="doCheck(this)">E <input type="CHECKBOX" name="sample6" onClick="doCheck(this)">F <input type="CHECKBOX" name="sample7" onClick="doCheck(this)">G <input type="CHECKBOX" name="sample8" onClick="doCheck(this)">H <input type="CHECKBOX" name="sample9" onClick="doCheck(this)">I <input type="CHECKBOX" name="sample10" onClick="doCheck(this)">J </body> </html>The display results are as follows: